# f(x) Calc vs MistakeBook

The clearest difference is price: f(x) Calc at Free against MistakeBook's $1.99. f(x) Calc also leads on update cadence (every 10 days vs monthly). MistakeBook's advantage is in-app purchases (none vs 1) and iOS requirement (13.0 vs 16.6). On ads and device support there is nothing between them.

f(x) Calc is free to download; MistakeBook costs $1.99 up front. f(x) Calc sells 1 one-off in-app purchase. MistakeBook asks for nothing beyond the download.

f(x) Calc ships an update every 10 days, MistakeBook monthly. Both last shipped on October 31, 2026.

## The numbers

| Metric | f(x) Calc | MistakeBook |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/fx-calc/id6760609257/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 10 days** | Monthly |
| Monetization | **Free** | Paid |
| Size | 5 MB | 26 MB |
| Requires iOS | 16.6 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | +4 |
| Developer | [David Russell](https://appshunter.io/developer/1104864276) | [Xiamen City Fanyou Network Technology Co., Ltd.](https://appshunter.io/developer/1842524161) |

## What reviewers say

### f(x) Calc

[App page](https://appshunter.io/ios/app/fx-calc/id6760609257)

A full-featured scientific calculator designed for math and science students. It offers natural math entry and includes built-in examples to aid learning. A simplified Junior mode is available for everyday use.

**Highlights:** Natural Maths entry, Built-in learning examples, Junior mode for everyday use, Ideal for math and science study, Full-featured scientific calculator

**Features:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Access | Free | one-time |


### MistakeBook

[App page](https://appshunter.io/ios/app/mistakebook-wrong-answer-log/id6770173206)

Log and review incorrect answers to improve learning. Organize mistakes by subject and topic, and utilize spaced repetition to reinforce weak areas. Track progress with visual charts and daily check-ins for effective test preparation.

**Highlights:** Log mistakes with photos and notes, Organize by subject and custom tags, Spaced repetition review mode, Ebbinghaus forgetting curve schedule, Progress charts and stats dashboard, Data import/export backup

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is f(x) Calc free?

f(x) Calc is free to download, with in-app purchases available.

### Is MistakeBook free?

MistakeBook costs $1.99, with no in-app purchases.

### Do f(x) Calc or MistakeBook have ads?

Neither f(x) Calc nor MistakeBook shows ads.

### Which is updated more often, f(x) Calc or MistakeBook?

f(x) Calc ships an update every 10 days, and MistakeBook monthly. Most recently, f(x) Calc was updated on October 31, 2026 and MistakeBook on October 31, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*