Privacy Policy

The short version

1. Who we are and how to reach us

MathTalk, PBC is a public benefit corporation based in Cambridge, Massachusetts. We make Math! Everywhere! ("M!E!"), and we are responsible for the information collected through it and through our websites. The companies listed in Section 10 help us run them.

• Mail: MathTalk, PBC, 99 Bishop Allen Drive, Cambridge, MA 02139
• Email: info@mathtalkpbc.com
• Phone: (800) 944-1569

The same team answers questions about this policy, our Terms of Service and the research study.

2. What this policy covers

This policy covers:

• The Math! Everywhere! app for iPhone and iPad, including the family testing round from October 20, 2026 to January 20, 2027. There is no Android version.
• Our servers that run the app, and the tools our team uses to write missions and map places ("content tools").
• The research study connected to the app (Section 11).
• Our websites, matheverywhere.com and math-talk.com, with their sign-up forms and newsletters.

It does not cover our older app, Measure! Everything!, which has its own privacy policy.

Math! Everywhere! is for families in the United States: children up to grade 8, including younger children who explore with a grown-up, and the parents and caregivers who use the app with them. In this policy, "you" means a parent or caregiver, a teacher, or a website visitor, and "your child" means a child whose profile is in your family account. "Parent" includes a legal guardian.

Our Terms of Service set the rules for using the app and the websites.

3. Words we use

• Towers: real places on the app's map where your child finds math, like parks, shops and landmarks.
• Missions: short math activities, often tied to a tower.
• Trails and events: walking routes with stops, and community events, where a grown-up can check a child in.
• MathGlasses: the app's camera feature. Your child points the camera at something to find the math in it.
• MathJournal: your child's space to write, draw, add photos and measurements, and record their voice.
• Math gifts: things your child makes with the app's tools (like photos, drawings, voice, measuring and data stories) and saves to the journal.
• "Talk to Me!": two different features share this name. In your child's journal, it gives AI feedback on your child's work (Section 7). For grown-ups, it is an AI chat.
• Math Moments: activity ideas for grown-ups.
• MathBuck$: points your child can earn in the app. They are not money, and the app does not award them during the testing round (Section 20).
• Research choice and community feed choice: two choices you make when you sign up (Section 4).
• Testing group: the group your family joined through, like Franklin Park Zoo families.
• ID number: a random code our system gives each grown-up, family and child. It is not a name, but our records link it to one.

4. How a family signs up, and what you agree to

A grown-up signs up. A parent makes the account with an email and password, Sign in with Apple, or a Google account. You give a display name. You can add your household ZIP code, and you pick your testing group.

One required agreement and two choices. When you sign up, you agree to one thing and choose two others:

1. Using the app (required). You agree to this policy and our Terms of Service so your children can use the app.
2. Research (your choice). With research on, you get a short survey when you start, a check-in once a month, and a short question after a finished journal entry, and the app sends analytics (Sections 8 and 11). With research off, the app shows none of these and sends no analytics.
3. Community feed (your choice). The feed is not open yet, and nothing your family makes is shown to other families. Before it opens, we will tell you what other families will see and ask you again.

You make both choices when you sign up, and you can change either one at any time in the app's settings. Saying no to them does not change how your child uses the app.

We keep a record of what you agreed to. Our server saves which version of this policy you agreed to (like "2026-10"), when you agreed, your two choices, and every later change with its date. Our servers stamp the dates, and the app cannot edit or delete the history. We keep it as proof of your permission (Section 16).

Adding children. After you agree, you add each child: first name, an optional last initial, grade, and birth date. We keep only the month and year of the birth date. The day is dropped before anything is saved. You can also pick a picture (avatar) and a color for each profile.

How you show that you are the parent. You confirm in the app that you are the child's parent or legal guardian before you add a child.

Families who joined before October 14, 2026. The next time you open the app, it shows you this policy and asks for your choices. Your children can use the app again after you agree.

Children in grades 6 to 8 also join through a parent's account, like everyone else, and use the app on a grown-up's device.

Children never get their own login, email address or password. Every child uses the app through a profile in a parent's account.

Teachers. Some teachers made accounts at an earlier stage. The app does not offer teacher sign-up during the testing round (Section 12).

Before a parent agrees. Before a parent has agreed, the app sends nothing about the person using it to us or to any other company, other than what signing in needs and a crash report if the app crashes (Section 8).

5. What we collect and why

This section lists everything we collect, grouped by whose information it is. Section 16 says how long we keep each kind.

5.1 From parents and caregivers

• Account details: your email address (from your sign-in), your display name, how you sign in (email and password, Apple, or Google), whether you use the app as a caregiver or a teacher, when your account was made and changed, and when you last signed in. Why: to run your account. Your password is checked by Google's sign-in service (Firebase Authentication); our servers do not store it. If you use Sign in with Apple, Apple may give us a private relay email address instead of your own.
• Household ZIP code (optional). Why: to show places near you, to plan partner businesses and walking routes, and to report to the grant that funds our study which communities the program reaches. It is saved on your account, not on your child's profile. With research on, it is also sent with every analytics event and saved with survey answers (Sections 8 and 11).
• Testing group: the group your family joined through, for example families from Franklin Park Zoo, or MathTalk's own team and network. Why: to compare groups in the research, and to keep our own team's test devices out of research results. Some group names show a connection to MathTalk or to the zoo.
• Settings: your language (English or Spanish), whether the app shows you tips, and which tips you have seen; for each child, whether tip bubbles show and the profile color. Why: to show the app the way you set it.
• Your agreement and choices: the record described in Section 4. Why: proof of your permission, and to follow your choices.
• Your family: a family name (usually your last name and the word "Family"), the grown-ups and children in it, which grown-up made it (the "primary grown-up", who can ask us to delete it), and the date of any deletion. Why: to know who can manage each child.
• Ratings: your likes and dislikes on Math Moments, saved with your family's or your account's ID number. Why: to improve the ideas.
• Reports about places and photos: reporting a place or a photo from inside the app is not open during the testing round (Section 20). If you tell us about a problem with a place, we keep your message (below). Place reports made with earlier test versions, before September 29, 2026, saved the device position the app sent with them; Section 16 says how long we keep them.
• Messages to us: emails, bug reports, TestFlight feedback (which can include screenshots), and what you tell our team. Why: to answer you and fix problems. Screenshots show whatever was on your screen, including your child's work, so please leave out faces and names.
• Community team: if you give them to our community team, your phone number for text reminders, and notes on what you tell us. Only MathTalk team members see them. Why: to support your family during the testing round.
• Website sign-ups and newsletters: Section 5.4.

5.2 About your child, through the app

You give us some of this when you add your child. The rest comes from your child's use of the app.

• Profile: first name, optional last initial, grade (from early childhood through grade 8), birth month and year, avatar, profile color, and a research study number (like "PT_12") that our system gives every child profile. Why: to show math that fits your child's grade and age, and to keep research files free of names. Our system uses the birth month and year to know whether your child is under 13. That result is worked out each time and not saved. If a birth date looks wrong, our system treats the child as under 13 and marks the profile for a check. If your child's grade changes, for example at a new school year, we keep the earlier grade, the date it changed, and any note our staff added.
• Progress: missions started and finished, your child's answers on mission cards (with which card they answer), badges, streaks, today's activity level, and progress in games and puzzles. Why: to run missions, badges, streaks and levels. Card answers are saved exactly as the app sends them. Today they are short answers, like a word or a number.
• Check-ins: when a grown-up checks your child in at a trail stop or a community event, we save which stop or event, the time, and which grown-up did it, in your child's record and activity log. No location is saved with it. Why: to track your family's progress along a trail and at events.
• MathBuck$: the app is built to keep the points your child earns, with which mission or badge earned them and when. During the testing round it does not award any points, so this record stays empty. Spending points at partner businesses is not open yet (Section 20).
• Class connection (only if you connect your child to a class): which class, and when your child joined or left it. Why: class features (Section 12).
• Location for the map: Section 6.
• What your child makes: MathJournal entries (writing, drawings, photos, voice recordings, measurements, data stories and circle art) and MathGlasses photos are saved on your phone or tablet, not on our servers. The exception is the AI features in Section 7: when your child uses them, the app sends what your child is working on, including photos, to Google's Gemini service. Voice recordings are turned into text in the app; the recording itself stays on the device unless you share it, and only the text goes to the AI company. The app's Share button sends a journal page, photo or recording to another app that you choose, like Messages or email; what happens next is up to you and that app. Please keep the Share button for grown-ups.
• Research answers (research on only): Section 11.
• Analytics (research on only): Section 8.
• Device details: the model of your phone or tablet, its system version and screen size, and the app version. These go with analytics events (research on only) and with crash reports, and help us fix problems.
• Device permissions: the app asks your permission before it uses the camera (MathGlasses and photos), the microphone (voice recordings), your location while you use the app (the map), motion (the step counter) and notifications. You can turn each one off in your device's settings; the feature that needs it then stops working.
• What the app keeps on the device: besides the journal, the app saves your settings and some account and profile details on your phone or tablet, which can include your child's name, grade and age, your email address and your ZIP code. Anyone who can open your device can see what is saved in the app.

5.3 From teachers

• Account details: as in Section 5.1.
• Classes: class name (often the teacher's name and room), grade, school year, co-teachers, and the class code. Why: to run class features.
• What teachers see about children is in Section 12.

5.4 From website visitors

matheverywhere.com

• "I want to test the app" form: your first name, last name (optional), email, your children's first names (optional) and each child's age or grade, and your city (optional). We also record the page's language, the website's name and the time. Why: to invite you to the testing round and contact you about it. Children's information on this form comes from you, the parent.
• "Keep me in the loop" newsletter: your first name and email. Why: to send you news about Math! Everywhere!.
• Where it goes: the form sends what you type to our sign-up service at Vercel, which adds it to a Google Sheet kept in a Google account managed by a member of our team.
• Visits: no cookies, analytics or trackers (Section 13).

math-talk.com

• Newsletter form (HubSpot): your email, first and last name, and how you describe yourself (for example, parent or educator).
• ShapeFinder access form (HubSpot): your email and first and last name.
• Contact and "Request a Demo" forms: your first and last name, email, organization, job title, city, state, postal code, subject, type of organization, and your message. These entries are saved in our website system, hosted by WP Engine, and sent to our team by email.
• Why: to send the newsletter, give access to ShapeFinder, and answer you.
• Visits: Section 13.

5.5 From partner businesses

If your business is a partner, we keep its name, address, website, a contact person, and the details about the business and its owner that appear in the app (like a short story). Why: to show partner places in the app and, from January 2027, to run MathBuck$ spending. Families see the business details and the story in the app.

5.6 What we do not collect

• Your child's full birth date (only the month and year).
• Your street address or your home's location.
• An email address, phone number or login for your child.
• Your device's location when the app is closed or in the background. The app asks for location only while it is in use, and it does not ask for your contacts.
• Payment details. The app is free and sells nothing.
• Government ID numbers.

Children cannot post anything for the public or for other families in the app.

6. Location: what leaves your phone and what we do not keep

To show towers near you, the app needs your device's location while the map is open. This is what happens to it.

What leaves your phone

• To our servers, with each map request: your device's latitude, longitude and direction (heading). We use it to find nearby towers and send them back. We do not save it in your family's records. Our server records keep each request, with the location and your device's internet address, for 30 days, then delete it automatically.
• To the map company: your device's internet address and which part of the map is on your screen, so it can send the map pictures. The map company is Mapbox, in the United States. Mapbox's own data collection (telemetry) is turned on in our app, so Mapbox also receives information about how the map is used on your device, which can include your device's location while the map is open.
• To websites that host place photos: your device's internet address, when a photo loads.
• With research on, in analytics: which towers your child taps, whether your child was near a tower, and step counts from the app's step counter. Over time, this can show places your child has been.
• Your household ZIP code, if you give it (Section 5.1).
• Old place reports: place reports made with earlier test versions, before September 29, 2026, saved the device position sent with them (Section 16).

What we do not keep

• A track of where you go. The app sends your device's location to our servers only with map requests, and we do not build a record of your movements from them. Mapbox's telemetry (above) can also receive your location while the map is open.
• Which towers your child has visited. That record stays on your device.
• The location where a photo was taken. We do not use it. Photos sent to the AI company may carry the location data your device adds to photos; we are confirming this. To be sure, turn off location for the camera in your device's settings.

We never use location for ads, never sell it, and never show it to other families.

7. AI in the app

"AI" here means computer programs that write a reply to what they are given. Our own servers do not run any AI. When an AI feature is used, the app sends the request from your phone or tablet straight to the AI company, and the reply comes straight back.

AI features for children: MathGlasses, and the journal's "Talk to Me!" and "Check My Work"

These features use Google's Gemini AI service, in the United States. The app sends each request from your device straight to Google:

• MathGlasses sends the photo your child takes, your child's grade, and the math unit your child is working on, and gets back math prompts about what is in the photo.
• "Talk to Me!" in the journal sends your child's first name and grade, your child's answers and writing in that entry, voice recordings as text, and the entry's photos and drawings (up to 10 photos in a session), and gets back feedback.
• "Check My Work" sends your child's work on the task, and gets back a check.

Because the request comes straight from your device, Google also sees your device's internet address. Google handles what it receives under its Gemini API terms. We have not yet confirmed with Google how long it keeps what it receives, or whether the plan we use lets Google use it to improve its AI. We will update this policy when we have, and we will not agree to let Google use your child's photos, journal or voice to train AI without asking you first.

Using these AI features is part of the agreement you accept to use the app; there is no separate switch for them. If you do not want your child to use them, do not open MathGlasses or tap "Talk to Me!" or "Check My Work". The rest of the app works without them.

"Talk to Me!" for grown-ups. This is an AI chat for parents and caregivers. The app sends your messages, and may include your children's first names and grades so the replies fit your family, to Anthropic, a US AI company, to get a reply. Under Anthropic's business terms for the service we use, Anthropic does not use what it receives to train its AI, and we have not agreed to let it. Anthropic deletes what it gets within 30 days, unless its safety systems flag a message; then it may keep that message for up to 2 years. The chat is for grown-ups, not children.

AI can be wrong. AI replies can be wrong, odd or not right for a child. No person checks each reply before it is shown. Explore together, and tell us if something seems off.

A tip. Take photos of things, not faces. Do not photograph papers that show a name or a school.

Training AI. We will not let any company use your child's photos, journal or voice to train AI without asking you first. Anthropic's terms do not allow it (above). For PostHog, see Section 8. For Google's Gemini service, see above.

Our research team's use of AI. Our research team does not read your child's journal entries during the testing round.

8. Analytics, and what research off changes

We use PostHog, an analytics company, to see how the app is used, to fix problems, and for the research study. The app sends analytics only if research is on for your family. Test versions from before October 2026 sent analytics for every family; if you still have one of those, update to the current version.

• What it records: events such as opening and closing the app; switching between the grown-up and child profiles; MathGlasses modes and cards; journal activity, as counts only (how many photos and drawings, how many words, how long a voice recording was, and whether an entry was shared); the type of each AI reply and whether it pointed out a likely mistake; tools started, finished or stopped; missions accepted; tower taps (the kind of place, and whether your child was near it); tips shown and dismissed, with the app's language; math gifts started and saved; Math Moments saved; surveys and quick questions started, finished or skipped; how many children a grown-up is using the app with; and step counts.
• With each event: your child's exact age and grade, your household ZIP code, your testing group, the ID numbers for your child, for you and for your family, the app version, and your device model, system and screen size.
• What it does not get: names, email addresses, journal words, photos, drawings or recordings.
• Linked to your child in our records: PostHog gets the same ID numbers our database uses, so we can link analytics to your child's profile. PostHog itself does not get names.
• Internet address: since about September 28, 2026, the app is set so that PostHog does not keep your device's internet address. We are confirming in PostHog's own settings that it also does not guess your location from it. Events sent from September 22 to about September 28, 2026 included the internet address and a location guessed from it (city, ZIP code and map position). We will delete that information by November 14, 2026.
• How we use it: to fix and improve the app, and for research. Never for ads, to contact your child, or to build a marketing profile.
• PostHog's own use: PostHog's terms let it use customer data, made anonymous, to improve its own products and AI models, unless the customer opts out, and opting out works only from then on. We are opting our project out. Data sent before the opt-out takes effect may already have been used that way, without names or ID numbers.
• Deleting it: Section 18.

The app does not use Google Analytics for Firebase. Crash reports go to Google (Firebase Crashlytics), with the device model, system version, what the app was doing when it crashed, and a random code for the app on your device, and nothing that names your child. Crash reports are sent whether or not research is on.

9. Maps, places and photos from other companies

• Map places. Most towers come from Foursquare's open places data. Our team adds others, like partner businesses, trail stops and community spots. A computer picks most places from public maps, so a few may be wrong, closed, private, or not right for children. Our Terms of Service say how to stay safe.
• Place details. When you open a place, our server asks Foursquare for its details using only the place's ID. Foursquare gets nothing about you from our server.
• Place photos. Place photos load straight from the websites that host them: Foursquare and about 15 others, such as Yelp, Squarespace, Shopify, Wikimedia and some local businesses' own sites. Those websites see your device's internet address when a photo loads, as any website does. No person checks every place photo.
• Our own content. Some of the app's content, like community events and trail artwork, comes from our content system, Airtable, and the app loads some of it straight from Airtable, which then sees your device's internet address.
• The map itself: Section 6.
• Test tools. Our developer test tools include a place search that sends the device's location straight to Foursquare. They are for our team, and we are confirming that they cannot be reached in the version families get.

10. Who gets information, and why

We share information only as this section describes. We do not sell personal information, and we do not use it for ads. The app shows no ads and contains no advertising or ad-tracking code, and it does not ask to track you across other companies' apps or websites.

10.1 Companies that help us run the app and the websites

Their promises to us. We ask each company that gets children's information from us for its written promise to keep it safe and use it only to do its work for us, and we require each company to protect it at least as well as this policy does. Google Cloud (its Cloud Data Processing Addendum) and PostHog (signed October 5, 2026) have given us that promise. We asked Airtable for its agreement on October 7, 2026 and are completing it. Google's Gemini service, Mapbox and Niantic work under their standard terms, which we are reviewing.

Our team. People on the MathTalk team, including our community team and interns, see information as part of running the app and the study.

10.2 People in your family and your child's class

• Grown-ups in your family. Every grown-up in your family account can see your children's profiles and activity. Today each family account has one grown-up; adding another is not open yet (Section 20).
• Your child's teacher, only if you connect your child to a class (Section 12).

10.3 Researchers and our funder

• Boston College researchers help evaluate the program. They get only summaries with no names or ID numbers, made only from families with research on. So far they have received nothing from us, and they have no access to our database. Before anything more goes to them, we will ask you with a separate form (Section 11).
• Our evaluators. Two evaluators who work with us on the study can see survey and quick-question answers.
• Our funder, the Heising-Simons Foundation, gets reports with combined results and no names. We will not put your child's name, words, drawings or photos in any report or talk without asking you first with a separate form.

10.4 Legal reasons and safety

We share information if the law requires it, for example a court order, or if we believe it is needed to protect a child's or someone else's safety, or to protect the app from fraud or attack.

10.5 If MathTalk changes hands

If MathTalk merges with or is bought by another organization, we will require that organization to protect your information at least as well as this policy does, or to ask you again before using it differently.

11. The research study

What it is. MathTalk is studying whether the app helps families notice and talk about math in everyday life, and how to make it better. The study is connected to a research grant from the Heising-Simons Foundation that runs from November 2026 through December 2028. Researchers at Boston College help evaluate the program.

It is your choice. The research choice is separate from using the app (Section 4). You can turn it on or off at any time in the app's settings.

With research on:

• a short survey when you start (October only), and a check-in on October 28, November 18 and December 16, 2026, and January 20, 2027;
• a short question after a finished journal entry, at most once a day;
• analytics (Section 8).

You and your child can skip any question.

Where answers go. The app saves survey and quick-question answers in Airtable, an online database company. Each answer is saved with your child's first name, ID number, grade and age; your name, email address and ID number; your ZIP code and testing group; and the app version. A quick-question answer is also saved with the title and text of the journal entry it followed. MathGlasses thumbs up or down, if your child gives one, are saved there the same way, with the AI prompt and the AI's description of the photo. Some earlier answers are also kept in an older Airtable base; we are deleting those copies.

Research files. The research study number on each child profile lets us build research files without names. Only families with research on are in research files.

Boston College. Boston College gets only summaries with no names or ID numbers, made only from families with research on. If Boston College later needs more, we will first ask you with a separate form approved by Boston College's review board, and we will have a data agreement with Boston College. Nothing more is shared unless you sign that form.

Small groups. We do not report results for any group of fewer than 5 families, because small numbers can point to one family.

Results without names. After we remove names, ID numbers and ZIP codes, MathTalk and Boston College may use combined results in reports and in future studies about how children learn math, only as Boston College's research plan allows.

Leaving the research. Turn research off in the app's settings. Surveys, quick questions and analytics stop, and we delete your research data that has names or ID numbers within 45 days. You keep the app. Results already combined with other families' results, with no names, ID numbers or ZIP codes, cannot be pulled back out.

12. Schools and teachers

A family program. During the testing round, Math! Everywhere! is a program for families. We are not working under an agreement with any school, and the app does not use school sign-in systems like Clever or ClassLink.

Class codes. Where your version of the app offers it, a parent can connect a child to a class with a code from the child's teacher. The teacher then sees your child's first name and last initial, grade, badges, streaks, and what kinds of activity your child did that day. The teacher does not see your child's journal, photos, answers or location, or your contact details. You can disconnect your child from the class at any time.

Teachers. Teachers who already have accounts can keep using them; the app does not offer teacher sign-up during the testing round. When a teacher closes a class, our system deletes it, with its list of children and its code, 30 days later.

If a school uses the app later. If a school uses Math! Everywhere! with its students, a written agreement with the school will add rules for that use, and we will update this policy before it starts.

13. Cookies and trackers on our websites

The app does not use cookies.

matheverywhere.com sets no cookies and uses no analytics or tracking. It loads its font from Google Fonts, so Google receives your device's internet address when the page loads. Vercel, which hosts the site, receives your device's internet address and browser details with each visit, as any web host does.

math-talk.com sets the cookies below when a page first loads. It does not ask first.

HubSpot also records page views with a code made from your browser's details (a "fingerprint"), and it can copy what you type into the site's other forms into HubSpot. Google and HubSpot may collect information about your visits over time and across different websites.

"Do Not Track." Browsers can send a "Do Not Track" signal. Our websites do not respond to it differently, because there is no common standard for it.

14. Emails and messages we send

• Sign-in emails (password resets and email checks) are sent by Google's sign-in service for us, from an address that ends in firebaseapp.com.
• Testing-round emails come from our team. Invitations to TestFlight come from Apple.
• Newsletters. You get them only if you sign up. Every newsletter includes a way to unsubscribe and our mailing address, and we stop within 10 business days after you unsubscribe.
• Text messages. If you give our community team your phone number, they may text you reminders. Tell them, or email us, to stop.
• Notifications. If you allow them, the app shows reminders on your device. These reminders are made on the device itself; no notification service receives information about you.
• We never send emails or texts to children.

15. Children's privacy: our notice to parents

This policy is our notice to parents under the Children's Online Privacy Protection Act (COPPA). In short:

• Who collects it: MathTalk, PBC (Section 1).
• What we collect from children and how we use it: Sections 5 to 9.
• Can children make information public? No. Children cannot post anything for the public or for other families in the app.
• Who we share it with, and why: Section 10.
• How long we keep it: Section 16, our written retention policy.
• Your rights and how to use them: Section 18.
• We do not ask a child to share more than an activity needs, and children can skip any survey question.
• We ask for a parent's permission before we collect information from a child. We do not rely on the exceptions that let some apps skip permission for device codes used only to run the app, or for voice recordings that are deleted right away.
• COPPA protects children under 13. We give every child in the app the same protections, at any age.

16. How long we keep information

We keep information only as long as we need it for the reason we collected it, then delete it. This table is our written retention policy. "Deleted" means removed so that it cannot be retrieved in the normal course of business. Deleted information can stay in our database backups for up to 14 more days.

17. How we keep information safe

• Our database and servers run on Google Cloud. Google encrypts the database on its disks, and the app and our servers talk over encrypted connections.
• Sign-in is handled by Google's sign-in service. Our servers do not store passwords.
• We keep database backups for 14 days so we can recover from mistakes, and our server records delete themselves after 30 days.
• We are adopting a written information security program for children's information, with a named person in charge, and we will review our risks and safeguards at least once a year.
• Some parts of our system answer anyone who has a child's ID number, without a sign-in. The ID numbers are long random codes, but they appear in our server records, analytics and survey records. We are changing these parts so that only a signed-in grown-up in the family can use them.
• No system is perfectly safe. If we learn that someone got your child's information without permission, we will tell you, and the authorities that the law requires, as soon as we reasonably can.
• What you can do: use a strong password, keep your device locked, and keep the app up to date. Journal entries are saved on your device, so anyone who can open it can see them.

18. Your rights and choices

For your child's information, at any time you can:

• See it. Ask us what kinds of information we have about your child, and for the information itself.
• Get a copy. Email us, and we will send you a copy.
• Correct it. Change your child's name, grade or color in the app, or ask us.
• Have it deleted, by email (below).
• Stop further collection or use. Turn research off, ask us to delete your child's profile, or tell us to stop. If you tell us to stop all collection, your child can no longer use the app, because the app cannot work without it.

Deleting a child's profile or your family account. During the testing round, email us to delete a child's profile or your whole family account. We check that you are the parent, lock the profile or the family, and our system deletes it, with every record about that child, from our database 30 days later. Journal entries saved on your device are deleted when you delete them in the app or delete the app.

Copies at other companies. Our system does not tell other companies when we delete something, so our team deletes the copies at PostHog, Airtable and any other company in Section 10 that keeps a copy, by hand, within 45 days, and emails you when it is done. If Anthropic's safety systems flagged a grown-ups' chat message, Anthropic may keep that message for up to 2 years.

Your own account. Deleting the family does not close your own sign-in. To close it and delete your account details, email us. We do it within 45 days.

How to ask us. Email info@mathtalkpbc.com, call (800) 944-1569, or write to us at the address in Section 1. We first check that you are the parent, for example by asking you to write from the email address on your account. We answer within 45 days. It costs nothing.

Leaving the research: Section 11.

Grown-ups, teachers and website visitors can also see, copy, correct or delete their own information by emailing us. Every newsletter has an unsubscribe link.

Wherever you live. Some states give their residents more privacy rights. We give the rights in this section to everyone who uses Math! Everywhere!, wherever they live in the United States, and we never treat you differently for using them.

19. Where we keep information, and who can use the app

Math! Everywhere! is for families in the United States. Our database and servers run on Google Cloud in the United States, and our analytics run in PostHog's US cloud. Our websites can be visited from anywhere, but the app and the testing round are only for people in the United States.

20. Parts of our system that are not on yet

Some parts of our system are built but not used by the app today, or are planned. Before we turn any of them on, we will update this policy, and, where the law requires it, ask you first.

• MathBuck$ earning and spending. The app does not award MathBuck$ during the testing round. Spending them at partner businesses is planned for January 2027 in Greater Boston; this will record which business, which item and when, and which children took part.
• Family Hub (planned for November to January): family "math days", streaks for the whole family, and counts for groups of families. It needs an activity log that can save the kind of activity, which tower, when and for how long, a code for the device, your time zone, and other details about the activity. Today the log records only check-ins (Section 5.2).
• The community feed: MathGlasses posts from families nearby, checked by our staff before they show.
• Grown-ups' map tools: rating places, favorites, tips, reporting or editing a place, suggesting new places, and a contributor badge. Built, and switched off for the testing round.
• Adding another grown-up to your family with an invite code, and sharing a child's profile with another household with a share code.
• Sharing a journal entry with your child's teacher, and teacher replies.
• Science of Sports progress: the dates and kinds of training tries, with no places.
• "Top 3 math places": this would need our servers to know which towers your family visits.
• School sign-in (Clever and ClassLink).
• Two-player (co-play) history, teacher invite codes that add a family to a class, and a log of what teachers do in the class dashboard.

21. Changes to this policy

If we change what we collect, use or share in a way that affects your child, we will update this policy with a new version, tell you in the app, and ask for your permission again before the change applies to your child. Smaller changes, like a new phone number, appear here with a new "Last updated" date. Ask us for any earlier version.

22. Contact us

MathTalk, PBC, 99 Bishop Allen Drive, Cambridge, MA 02139

• Email: info@mathtalkpbc.com
• Phone: (800) 944-1569