Apps by Peter Li
NumLock: Math Screen Lock app icon

Productivity

NumLock: Math Screen Lock

Peter Li

Free download In-app purchases
Open on Apple

About this app

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

Audience growth

Ratings growth

Steady
7-day gain +0
Ratings / day 0.0
30-day gain +0
US rating-count history
0 ratings
0 Aug 18, 2026 · 0 ratings Aug 18, 2026

Baseline captured. Growth appears after the crawler observes a changed rating count.

Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.

Price tracking

Price intelligence

1 captured event
Current Free
Historical low Free
Paid → free
Price history
Current Free
Free Aug 18, 2026 · Free Aug 18, 2026

First snapshot captured. The trend line starts after the next crawler price observation.

  1. First observed Aug 18, 2026 · 1:21 AM Free

Screenshots

NumLock: Math Screen Lock iPhone screenshotNumLock: Math Screen Lock iPhone screenshotNumLock: Math Screen Lock iPhone screenshotNumLock: Math Screen Lock iPhone screenshotNumLock: Math Screen Lock iPhone screenshotNumLock: Math Screen Lock iPhone screenshot