Serial Addition — Free PASAT-Style Working Memory Test

Add each number to the one before it — not the total.

Working memory
4 min
Hard

Practise adding each new number to the one immediately before it. If the sequence is 3, 5, 2, answer 8 and then 7 — not a running total. This visual browser exercise is inspired by serial-addition tasks, but is not the standardized auditory PASAT or a clinical assessment.

Play Serial Addition

How it works

1Numbers arrive one at a time, at a fixed pace.

2Add each one to the PREVIOUS number — not the total.

3Then discard it. The answer you just gave is dead weight.

How to play

1
Numbers arrive one at a time
A new number appears at a fixed pace. Each one stays only briefly.
2
Add it to the PREVIOUS number
Not to your running total. If you see 3 then 5 then 2, the answers are 8 then 7.
3
Keep pace
The interval shortens as you level up. The moment you fall behind, the next number is already gone.

What it trains

Hold and update information while under load. Updating — swapping stale contents out of working memory for fresh ones — is one of three separable executive functions and predicts reasoning performance.

Practice focus: Working memory
Based on: Gronwall, 1977; Miyake et al., 2000

Research background

These sources describe related tasks or concepts. HumanCalc adapts them for browser practice; a game score is not a clinical result.

Leaderboard

Weekly season resets every Monday. Scores show as Lvl 5.

Leaderboard

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Questions

Why is this so much harder than it looks?

Because you have to actively discard the answer you just produced. Holding onto it is the natural instinct and it is exactly what breaks the task.

Is this the same as the clinical PASAT?

No. It uses the adjacent-number addition rule, but displays numbers visually and has game-specific levels. The standardized clinical PASAT uses a defined auditory procedure. HumanCalc scores have no clinical interpretation.

What level should I aim for?

Choose a pace where you can keep track of the previous number. Compare your own accuracy at matching settings; the levels are not clinical norms.