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App Store Apps > Productivity > NumLock: Math Screen Lock
NumLock: Math Screen Lock icon

NumLock: Math Screen Lock

by Peter Li · Productivity · Free
On the App Store since April 2026 · Data updated 2026-10-23

NumLock: Math Screen Lock is made and published by Peter Li. AppBrain is an independent app data site and isn't affiliated with Peter Li. The app name, icon, screenshots and description belong to Peter Li and are shown as published on the App Store.

AppBrain's verdict

Last updated
April 14, 2026
Size
1.63 MB
Official page on the App Store

User feedback

Ratings and reviews on the App Store

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Store listing

By Peter Li, from the App Store
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Screenshots by Peter Li, from the the App Store listing
Description by Peter Li Written by the developer, not by AppBrain. Click to read.
Your phone unlocks over 150 times a day. What if each unlock made you smarter?

NumLock turns your screen time into brain time. Before you can open your blocked apps, solve a set of mental math problems. It takes seconds, keeps your mind sharp, and adds just enough friction to break the mindless scrolling habit.

HOW IT WORKS
Choose which apps to block. When you try to open one, NumLock presents math problems you solve on a number pad. Get them all right and your apps unlock for your chosen grace period. Simple, fast, and surprisingly satisfying.

ADAPTIVE DIFFICULTY
NumLock starts easy and gets harder as you improve. The 25-level system tracks your accuracy and speed, automatically adjusting to keep you challenged. Start with basic addition. Work your way up to multi-step equations, percentages, and large multiplication. You'll be amazed how fast your mental math improves.

GRACE PERIODS THAT FIT YOUR LIFE
After solving, your apps stay unlocked for a window you choose — 5 minutes for a quick check, 30 minutes for a balanced session, 1 hour for extended use, or until midnight for a full day off. When time's up, the lock comes back automatically.

STREAKS AND STATS
Build a daily streak by solving at least one session per day. Track your accuracy, average solve time, current level, and total problems solved. Watch yourself get faster and sharper over time. Your best streak is always recorded — can you beat it?

DESIGNED FOR ADULTS
NumLock isn't a parental control. It's a tool for people who want to take back control of their own screen time while training their brain. Think of it as a gym membership for your mind that activates every time you reach for a distraction.

FEATURES
— Block any app on your iPhone
— Mental math challenges on a clean number pad
— 25 levels of adaptive difficulty
— Streak tracking with best-streak records
— Accuracy and speed stats dashboard
— Configurable grace periods (5 min to all day)
— Light and dark mode
— No ads, no data collection, fully private

SUBSCRIPTION
NumLock requires an active subscription to use.
— Monthly: $4.99/month
— Annual: $39.99/year (7-day free trial)
Payment is charged to your Apple ID. Subscriptions auto-renew unless cancelled at least 24 hours before the end of the current period. Manage subscriptions in Settings → Apple ID → Subscriptions.

Terms of Use (EULA): https://apptato.github.io/numlockapp/terms.html
Privacy Policy: https://apptato.github.io/numlockapp/privacy.html
Official page on the App Store

Safety and technology

Found in the app by AppBrain
Price
Free
App size
1.63 MB
Content rating
Everyone

Technologies used by NumLock: Math Screen Lock

Releases

Updates seen on the App Store
Version
1.0
Launched
April 2026

No changelog data

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Rankings

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About the app and developer

About NumLock: Math Screen Lock

NumLock: Math Screen Lock is a productivity app developed by Peter Li.

User Ratings

The app has no ratings yet.

App Information

NumLock: Math Screen Lock is freely available from the App Store. The app size is 1.63 MB. The latest version available is 1.0. The last update was on April 14, 2026.

Technical Requirements

The app has a content rating of Everyone. The app has been available on the App Store since April 2026.

Developer information for Peter Li

Peter Li

Address:

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