Multitape Turing Machine vs Subtractor
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Multitape Turing Machine
This app simulates a mathematical model of computation, allowing users to explore how abstract machines manipulate symbols on a tape according to defined rules. It's a tool for understanding the fundamental principles of computer algorithms.
- Turing machine simulation
- Symbol manipulation on tape
- Abstract computation model
- Algorithm understanding
- State and head movement
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Multitape Turing Machine Simulator. A Turing machine is a mathematical model of computation describing an abstract machine, that manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, it is capable of implementing any computer algorithm. The machine operates on a memory tape divided into cells, each of which can hold a single symbol drawn from symbols from the alphabet of the machine. It has a "head" that, at any point in the machine's operation, is positioned over one of these cells, and a "state" selected from a set of states. At each step of its operation, the head reads the symbol in its cell. Then, based on the symbol and the machine's own present state, the machine writes a symbol into the same cell, and moves the head one step to the left or the right, or halts the computation. The choice of which replacement symbol to write and which direction to move is based on a table that specifies what to do for each combination of the current state and the symbol that is read. Suggestions: snowlukin@gmail.com
Subtractor
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Subtractor is a native iOS app coded in Swift, designed as a personal project to help students master subtractions effortlessly. With interactive exercises, customizable practice sessions, and progress tracking, Subtractor creates an engaging learning experience tailored to individual needs. Its sleek, distraction-free interface and responsive design make it a perfect tool for students, parents, and educators seeking to build strong foundational math skills.
Screenshots
Verdict
The clearest difference is update cadence: Subtractor at every 8 days against Multitape Turing Machine's every 8 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.
Multitape Turing Machine ships an update every 8 months, Subtractor every 8 days. The most recent releases landed on November 3, 2026 and November 8, 2026 respectively.
| Parameter | Multitape Turing Machine | Subtractor |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 8 months | Every 8 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 16.0 | 15.6 — better |
| Further details — not scored | ||
| Size | 2 MB | 0 MB |
| Age rating | 4+ | 4+ |
| Developer | Denis Mandych | David Kelen |
In-app purchases
Multitape Turing Machine
No in-app purchases
Subtractor
No in-app purchases
Questions
Is Multitape Turing Machine free?
Is Subtractor free?
Do Multitape Turing Machine or Subtractor have ads?
Which is updated more often, Multitape Turing Machine or Subtractor?
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