Transform Digits

⚙️ Settings

Lv 1
Streak 0
Max 0

Read the transformation rule, then tap READY.
Apply the rule to each digit mentally.
Enter the transformed digits in order.

Transformation Rule

Level 1 · Full

Rule hint always visible during input

Rule A

EVEN +1 | ODD -1
4 7 2 → 5 6 3
2.5

Memorize & transform...

✏️ Enter transformed digits in order

EVEN+1 / ODD−1
🎉 Correct!

Rule: EVEN+1 / ODD−1

Shown:

Answer:

Yours:

Streak: 0 | Level: 1

Support TOMOY Buy me a coffee

How to Play

1
A transformation rule is shown with an example. Read it, then tap READY.
2
A sequence of digits appears. Apply the rule to each digit in your head.
3
Enter the transformed digits in their original order.
4
At higher difficulties the rule hint fades or disappears — keep it in mind!
Example
EVEN+1 / ODD−1
4 7 2 → 5 6 3

4 (even) +1 = 5  ·  7 (odd) −1 = 6  ·  2 (even) +1 = 3

Are you sure you want to reset all data?
This will clear your scores and settings.

About Transform Digits

How This Task Works

Transform Digits presents a sequence of digits along with a transformation rule — for example, "add 1 to even digits, subtract 1 from odd digits" or "add 1 to digits below 5, subtract 1 from digits 5 and above." You must memorise the sequence and apply the rule to each digit before entering the transformed result.

Difficulty scales along three axes: (1) span length (3–12 digits), (2) rule complexity (four levels, A through D), and (3) rule visibility — the rule is displayed during input at early levels, shrinks at intermediate levels, and disappears entirely at advanced levels. From Level 5 onward, the rule changes randomly each round, requiring re-reading at the start of every trial.

This task demands simultaneous retention, transformation, and rule-switching. It is designed as the task in the TOMOY series that engages the greatest number of executive functions at once.

Task Background

Executive function research identifies three core components: updating, shifting, and inhibition (Miyake et al., 2000). Transform Digits incorporates all three — holding and updating the digit sequence, applying and switching between transformation rules, and inhibiting carry-over from the previous round's rule.

Compound transformation tasks of this kind share structural similarities with the cognitive processing required in everyday arithmetic, language processing, and logical reasoning. They are considered to load a broader combination of executive functions than simple memory tasks.

How to Use This App

Transform Digits is among the most demanding tasks in the TOMOY series. We recommend working through other tasks first before attempting it.

Read the rule carefully before each round, and try beginning the transformation while the digits are still being displayed. Maintaining the dual awareness of "hold and transform" is one approach that keeps the cognitive load high throughout the session. Difficulty adjusts automatically based on your accuracy.

Its Place in the TOMOY Series

Transform Digits is positioned as the culmination of the TOMOY series. Where other tasks load individual executive functions, Transform Digits requires them simultaneously within a single task. The retention and manipulation practised in Reverse Digits and Ascending Digits, the divided attention experienced in Dual-Task Reverse, and the inhibitory control trained in Filtered Digits — all converge here in the form of digit retention, rule application, and transformation execution.