4 vs Number Line
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
4
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Control the animation speed from 0 to 33 frames per second. The framerate is precisely calculated to allow you to synchronize for filming (with the strobes on or off). You can change the strobe brightness - from zero to a maximum of 1ms in duration. One neat trick to really get maximum reactions from new observers is two switch the strobes on and off while the animation is running - instantly turning the animation into a spinning blur, or instantly turning a spinning blur into a magic solid animation. Just for fun the strobes are RGB so you can change the strobe colour with the colour buttons, and there is a "secret" disco mode triggered by the button combo of W,R,G,B. On the settings screen you can configure your 4-Mation to work with your local wifi, and you can set its name. There are also advanced settings to secure the app in kiosk mode for public display - and you can also configure 4-Mation to run an animation with the different number of frames, or to use a replacement motor with a different gear ratio. There's a detailed breakdown of the app features here: https://youtu.be/mMFHqckvUVc
Number Line
This app provides an interactive number line for educational purposes, enabling users to visualize numbers, perform various math games, and practice rounding. Its simple interface supports zooming, swiping, and marking numbers with pins or freehand drawing.
- Infinite number line visualization
- Rounding practice (nearest 10, 100, 10,000)
- Number comparison
- Pinch-to-zoom functionality
- Swipe navigation
- Search for specific numbers
- Pin marking
- Freehand drawing tool
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An infinite number line to use in the classroom, with a simple design that allows for numerous maths games and challenges! • Ask the class to round to the nearest 10/100/10,000. • Visualise the size of numbers relative to one another, including negatives. How to use: • Zoom with a pinch • Swipe along the number line • Go to a number by typing in the search box • Drag and drop pins to mark numbers • Draw free-hand with the pen tool
Screenshots
Verdict
The clearest difference is update cadence: 4 at every 4 days against Number Line's every 15 months. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
4 ships an update every 4 days, Number Line every 15 months. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.
| Parameter | 4 | Number Line |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (5 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 5 — better |
| Update frequency | Every 4 days — better | Every 15 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 — better | 13.0 |
| Further details — not scored | ||
| Size | 8 MB | 16 MB |
| Age rating | 4+ | 4+ |
| Developer | Kevin Holmes | Blastoff Design |
In-app purchases
4
No in-app purchases
Number Line
No in-app purchases
