NumLock: Math Screen Lock
Math Challenge Screen Blocker
Only for iPhone
Free · In-App Purchases
iPhone
Train your brain every time you pick up your phone. Solve mental math to unlock your apps. Level up daily with adaptive challenges and streak tracking.
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
Ratings & Reviews
- This app has not received enough ratings or reviews to display an overview.
The developer, Peter Li, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Provider
- Peter Li
- Size
- 1.7 MB
- Category
- Productivity
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- NumLock Pro Annual USD 39.99
- NumLock Pro Monthly USD 4.99
- Copyright
- © 2026 Peter Li