Pick the two numbers out of five that produce the target with that operation. Order doesn't matter: for − and ÷ it's always bigger first.
Answer as many as you can before the clock runs out. Numbers get bigger as your streak grows; a miss drops you a level.
Example · ×
7×8=56
How it works
You get the numbers and the target. The operations between them are missing.
Fill each gap with +, −, × or ÷ so the equation equals the target. Exactly one combination works.
Normal order of operations: × and ÷ before + and −. Equations grow from two numbers to three, then four, as your streak grows.
Example · three numbers
4×3+2=14
4 × 3 = 12, then + 2 = 14.
Time limit
Operations
Starting level
Keyboard: press 1–5 to pick a tile, Esc to clear.
Time3:00
Correct0
Streak0
Level1
+=0
Time3:00
Correct0
Streak0
Level1
Results · fill in the operations
Correct0
Accuracy0%
Avg / answer—
Peak level1
By equation length
Numbers
Right
Wrong
Accuracy
Avg time
Misses to review
Results
Correct0
Accuracy0%
Avg / answer0s
Peak level1
By operation
Op
Right
Wrong
Accuracy
Avg time
Misses to review
Flashback · working memory (n-back)Best (3 min): —
How it works
Shapes appear one at a time. For each one, decide whether it matches the shape N steps back.
Start at 1-back (the shape right before). Do well and it moves to 2-back, then 3-back, where shapes have two colors and both colors must match too.
The first N shapes of each level are just to memorize. After that, answer before the next shape or it counts as Too slow.
Example · 2-back, shape only
Time limit
Starting level
Keyboard: F or ← for No match, J or → for Match.
Time3:00
Correct0
Accuracy—
Level1-back
Results
Correct0
Accuracy0%
Avg reaction—
Peak level1-back
By level
Level
Right
Wrong
Too slow
Accuracy
Shapedance · pattern matchingBest (3 min): —
How it works
You see several cubes, each with shapes laid out in a pattern.
Exactly two cubes show the same pattern. Click both. The others differ by a shape, a color or a position.
Patterns get busier as you level up. From level 3 the cubes are turned to different angles, and at level 4 they keep spinning. A turned copy still counts as the same pattern.
Example · level 1
Cubes 1 and 3 match. Cubes 2 and 4 each have one dot in a different spot.