Maths That Moves
Negative numbers are the first place school maths stops being about counting things you can hold. You can show a child three apples. You cannot show them −3 apples.
Negative Numbers — Calculate Game solves that the way good teachers do: with a number line. Every single question in the game comes with one, and the marker on it is draggable. Stuck on −3 + (−4)? Put your finger on the ball at −3 and walk it left four times. The answer is wherever you stop. Do that a few dozen times and the rule stops needing to be remembered — it's just what walking left feels like.
From there the course builds, one small idea at a time, all the way from "a minus sign means go left" to multiplying two negatives, dividing them, squaring them, and pulling square roots back out. One hundred levels, eight worlds, three questions each — short enough to fit in the gap before dinner, long enough to genuinely learn something.
🐧 A patient penguin
Get it wrong and nobody fails you. The penguin explains what went wrong, and the same question comes straight back so you can fix it.
📏 A number line on every question
Not decoration — a working tool. Drag the ball to count out the steps before you commit to an answer.
🎯 Three questions a level
Levels are deliberately short. Progress is constant, and nothing ever feels like homework.
📵 No accounts, no chat
Nothing to sign up for, nobody to talk to, no links out. Progress lives on the device and nowhere else.
How a Level Works
Every level follows the same rhythm, so there is never a moment of "what am I supposed to do here?"
Read the lesson card
Three short rules, a worked example, and a number line showing exactly where the answer lands. Then tap Start Level.
Work it out on the line
Drag the ball along the number line to count the steps. Nothing you do here is scored — it's your scratchpad.
Pick A, B, C or D
Right answers turn green and explain why. Wrong ones turn orange, explain the mistake, and hand the question back.
Collect your stars
Three questions later the level is done, and the penguin hands over one, two or three stars.
Stars are earned, not given
Stars depend only on accuracy, so guessing never pays. A quick finish adds a small time bonus to your score, capped low enough that speed can never beat getting it right.
A wrong answer never ends a run. There are no lives, no timers counting down and no game-over screen. The worst thing that happens is you lose a star and learn something — which is rather the point.
Learn the Number Line
The number line is the backbone of the whole game. Zero sits in the middle with a thicker mark. Positives run right, negatives run left, and every operation in the course becomes a movement along that line:
- Adding a positive — step right.
- Adding a negative — step left. Two negatives both pull left, so they pile up.
- Subtracting a positive — step left, which is how you cross below zero.
- Subtracting a negative — turn around and step right. Taking away a pull to the left is a push to the right.
Start at −3, walk 4 steps left, land on −7.
Later worlds keep the same picture even when the arithmetic changes. Multiplying by a negative is a flip across zero. Squaring lands you back on the positive side, no matter which side you started. Square roots walk the trip backwards. The line never disappears — it just gets more to say.
Eight Worlds, One Hundred Levels
The course runs in a straight line from the very first minus sign to mixed mastery questions. Each world drills one skill until it's automatic, then the next world builds on it. Levels unlock in order, and the map keeps score with stars.
Below Zero
Meet the minus and walk left.
Going Down
Take away and keep falling.
Mix & Match
Plus and minus in one puzzle.
Sign Factory
Two minuses make a plus.
Split the Sign
Share it out, keep the sign.
Power Up
Squares never stay negative.
Root Cave
Undo a square, find the root.
Grand Master
Everything, all at once.
300 questions, every one checked. The answers, the wrong options and the explanations were all generated and then independently re-verified — every sum recomputed, every distractor checked for being a plausible slip rather than nonsense, and every draggable number line checked to make sure the correct answer is actually reachable on it.
What's in the Game
🗺️ Level map
A winding path through the clouds. Cleared levels show their stars, the next one glows, and the rest wait behind a lock.
📖 A lesson before every level
Three rules, one worked example, one number line. Read it or skip straight to playing — it's there whenever you need it.
💡 Hints
A one-line nudge for the question in front of you, like "Start at −3 and move left 4." You begin with three.
🧮 Explanations, not just marks
Correct or not, every answer comes with the reason. "Two negatives both pull left, so add 3 and 1 and keep the minus sign."
⭐ Stars & scores
Up to three stars a level plus a running score. Replay any cleared level to chase a perfect run.
🔊 Sound & haptics
Chunky button clicks, a happy chime for correct answers, gentle taps as you drag. Both toggle off in Settings.
📱 iPhone & iPad
One purchase, both devices. The layout stretches to fill an iPad without turning the number line into a mile-wide ruler.
✈️ Works offline
All 100 levels ship inside the app. No connection needed to play — only to load an ad, and Pro removes those entirely.
Hints — and How to Get More
A hint is deliberately small. It doesn't hand over the answer; it tells you where to start walking. On −3 + (−4), the hint reads "Start at −3 and move left 4." The counting is still yours to do.
- You start with three hints.
- Using one on a question costs a few points on that question — but never a star, and never the level.
- Run out and the game offers you a rewarded video ad. Watch it and you get three more hints.
- The hint you were trying to use opens automatically once the ad finishes.
- Negative Numbers Pro gives unlimited hints with no ad at all.
Rewarded ads only ever play because you chose to watch one. If you'd rather not, close the offer and keep working the question out on the number line — that route is always open, and it's free.
Free to Learn. Pro to Finish.
Negative Numbers is free to download and free to play. Levels 1 to 10 — the whole first stretch of Below Zero — are yours with no purchase, no trial timer and no sign-up. That's enough to know whether the game clicks for your learner before anyone spends anything.
- Levels 1–10, in full
- Every lesson card and explanation
- The draggable number line on every question
- Stars, scores and level replays
- 3 hints to start, plus 3 more per rewarded video
- Shows banner and between-level ads
- All 100 levels, all 8 worlds
- No ads, ever — no banners, no video breaks
- Unlimited hints, no ad to watch
- Works on your iPhone and iPad
- Pay once. It does not renew.
No subscription, no coins, no energy timers. One optional purchase, and the game is finished for good. Restoring it on another device is a single tap on Restore Purchase in the Pro screen.
About the Ads
The free version is paid for by advertising through Google AdMob. Here is exactly where the ads appear, so there are no surprises:
- Banner ads — a small strip on the home screen, the level map and the level-complete screen. Never over a question, and never over the number line.
- Between-level video ads — a full-screen ad after roughly every second completed level. Never in the middle of a level, and never between the three questions inside one.
- Rewarded videos for hints — offered only when you've run out of hints and asked for another. Watch one, get three hints. Decline and nothing happens.
Negative Numbers Pro removes all three. Buying Pro is the only thing that changes what the app shows you — it never gates the number line, the lessons or the explanations behind a payment.
Before any tracking happens, iOS asks for your permission through App Tracking Transparency. Decline and the game still works exactly the same — you simply see non-personalised ads. See the Privacy Policy for the detail.
For Parents & Teachers
The course covers the standard integer-arithmetic sequence taught around ages 10–14 — UK Key Stage 3, US middle-school grades 6–8, and the equivalent elsewhere. It also works as a refresher for older students who never quite made peace with the minus sign.
📚 Ordered, not random
Addition, then subtraction, then mixed, then multiplication, division, squares, roots and mastery. Each world assumes the one before it.
🧠 Mistakes are the lesson
Wrong options aren't random numbers — each is a classic slip (sign dropped, negatives subtracted instead of added). Choosing one shows exactly which slip it was.
🔒 No data leaves the device
Stars, scores, hints and settings are stored locally. There is no account, no leaderboard, no cloud profile and no messaging.
🧾 One honest purchase
A single $4.99 unlock behind the standard App Store purchase confirmation. No coins, no consumables, no pestering pop-ups mid-question.
Progress can be wiped at any time from Settings → Reset all progress, which clears every star, score and unlocked level on that device.
Screenshots
Tap any image to view it full screen.
On iPhone
On iPad
Frequently Asked Questions
What age is it for?
It suits roughly ages 9 and up — anyone meeting negative numbers for the first time, revising them, or wanting the multiplication and square-root rules to finally stick. There's no reading-heavy text and no timer pressure, so slower readers aren't penalised.
How much is free?
Levels 1 to 10, complete with their lessons, hints, explanations and stars. Levels 11 to 100 need the one-time Negative Numbers Pro unlock.
Is Pro a subscription?
No. It's a single $4.99 purchase that never renews. It unlocks all 100 levels, removes every ad and makes hints unlimited, on both your iPhone and your iPad.
Can I lose a level or run out of lives?
No. There are no lives, no energy meters and no fail state. A wrong answer costs points and stars, explains itself, and lets you try again immediately.
Do I need the internet?
Only for ads. All 100 levels are stored inside the app, so the game plays perfectly on a plane or in the car. Pro players never need a connection at all.
Does it sync between devices?
Progress is stored on each device separately — there's no account and no cloud profile. A Pro purchase, however, follows your Apple Account: tap Restore Purchase on a second device and everything unlocks there too.
Are the ads suitable for children?
Ads are served by Google AdMob and filtered to match the app's App Store age rating. If you'd rather have none at all, Pro removes every ad permanently.
How do I start over?
Open Settings inside the game and tap Reset all progress. It clears every star, score and unlocked level on that device, and asks you to confirm first. A Pro unlock is not affected.
Privacy Policy
Last updated: July 2026
1. Introduction
This Privacy Policy describes how Negative Numbers — Calculate Game ("the App," "we," "our," or "us") handles information. The App is an educational maths game for iPhone and iPad.
We respect your privacy and are committed to protecting it, and we have kept the App's own data collection at zero.
2. Information We Collect
We do not collect personal information. The App has no accounts, no sign-up, no login and no user profiles. Everything the game remembers — your unlocked levels, stars, scores, hint count and sound and haptics settings — is stored locally on your own device and is never transmitted to us.
- We operate no servers of our own and receive no data from the App.
- The App does not ask for your name, email address, age or any other personal detail.
- The App does not access your photos, contacts, location, microphone or camera.
- The App contains no chat, no messaging, no user-generated content and no social features.
- We do not operate our own analytics.
- Some limited data is processed by our third-party advertising provider, as described in section 3.
3. Advertising (Google AdMob)
The free version of the App displays advertisements supplied by Google AdMob. These take three forms: a banner on the home, level map and level-complete screens; a full-screen video ad after approximately every second completed level; and an optional rewarded video that you may choose to watch in exchange for three hints.
To serve and measure these ads, Google may collect and process certain information, such as a device advertising identifier, general device and network information, coarse location inferred from an IP address, and app interaction data. This is used to deliver, cap, measure and (where permitted) personalise advertising. Ad requests are filtered to match the App's App Store age rating.
Your progress data is never shared with the advertising provider. Ads are supplied by Google's network; we do not select individual advertisers and do not receive information about you from them.
You can read how Google uses information from apps that use its services at policies.google.com/technologies/partner-sites.
App Tracking Transparency. On iOS, the App uses Apple's App Tracking Transparency framework to ask for your permission before any tracking across other companies' apps and websites takes place. If you decline, the App still works exactly as before and you will still see ads — they will simply be non-personalised. You can change this choice at any time in Settings → Privacy & Security → Tracking.
Purchasing Negative Numbers Pro removes all advertising from the App, and with it the ad-related data processing described above.
4. Children's Privacy
The App is designed for learners, including children, and is built accordingly: no accounts, no personal data collection, no chat, no user-generated content and no links out to social networks. We do not knowingly collect personal information from children.
We are committed to complying with the Children's Online Privacy Protection Act (COPPA), the UK Age Appropriate Design Code, the GDPR and similar regulations. Advertising is handled in line with the App's App Store age rating and the consent mechanisms described in section 3. Parents who would prefer their child to see no advertising at all can remove it permanently with the one-time Pro purchase.
If you believe a child has provided us with personal information, please contact us using the details in section 8 — although, because the App collects none, there is normally nothing for us to hold or delete.
5. Purchases
The App is free to download. An optional non-consumable in-app purchase, Negative Numbers Pro ($4.99, one-time), unlocks all 100 levels, removes all advertising and makes hints unlimited. All purchases are processed securely by Apple through the App Store. We do not receive or store your payment information — we are told only whether the unlock is active on your device.
6. Data Sharing and Retention
We do not sell, rent or trade data, because we do not hold any. The only third party that processes information through the App is our advertising provider (Google AdMob), solely to serve and measure ads in the free version. Locally stored progress remains on your device until you reset it in Settings or delete the App.
7. Changes to This Privacy Policy
We may update this Privacy Policy periodically. Any updates will be reflected on this page with a new "Last updated" date.
8. Contact Us
If you have any questions or concerns about this Privacy Policy, please contact:
Terms of Use
Last updated: July 2026
1. The App
Negative Numbers — Calculate Game is an educational game provided for personal, non-commercial use. It is free to download and supported by advertising in its free tier.
2. In-App Purchase
Negative Numbers Pro is a non-consumable in-app purchase priced at $4.99 (or the equivalent in your local currency). It unlocks all 100 levels, removes all advertising and grants unlimited hints.
Payment is charged to your Apple Account at confirmation of purchase. It is a one-time purchase and does not renew. Because it is non-consumable, it can be restored free of charge on any device signed in to the same Apple Account using the Restore Purchase button on the Pro screen.
3. Refunds
Refund requests are handled by Apple in accordance with the App Store refund policy. To request one, visit reportaproblem.apple.com.
4. Advertising
The free tier displays banner ads, full-screen ads between levels, and optional rewarded video ads that grant hints. Rewarded ads play only when you choose to watch one. Purchasing Pro removes all advertising.
5. Your Progress
Stars, scores and unlocked levels are stored on your device only. We hold no copy and therefore cannot recover progress lost by resetting it, deleting the App or replacing your device. A Pro unlock, being tied to your Apple Account, can always be restored.
6. Educational Content
The maths in the App has been generated and independently verified for correctness, and follows standard conventions for integer arithmetic. It is intended to support learning, not to replace a curriculum or a teacher. If you believe a question or explanation is wrong, please tell us — we will check it and correct it.
7. Contact
For questions about these terms, contact: contactscienceaplus@gmail.com
Start at Level 1
Ten levels, no purchase, no account — just a number line, a penguin and the moment the minus sign stops being scary. Negative Numbers — Calculate Game is free on iPhone and iPad, and Negative Numbers Pro opens all 100 levels and removes every ad for a one-time $4.99.
Need help, or spotted a question that looks wrong?
Email contactscienceaplus@gmail.com and we'll get back to you.