Mental math tricks for faster solves

Enigma's timer rewards quick arithmetic. None of it needs talent — the fast players just use a small kit of shortcuts that turn awkward calculations into easy ones. Here are the ones that matter for number puzzles.

Multiplying by 5: halve, then ×10

18 × 5  →  18 ÷ 2 = 9  →  90

Any number times 5 is that number halved, times ten. For odd numbers, the half ends in .5 and the ×10 clears it: 27 × 5 → 13.5 → 135. This is nearly always faster than direct multiplication.

Multiplying by 9: ×10 minus one copy

9 × 14  →  140 − 14 = 126

Nine is "ten minus one", so multiply by ten and subtract the number once. The same idea generalizes: ×11 is ×10 plus one copy (11 × 14 = 140 + 14 = 154), ×8 is ×10 minus two copies for small numbers.

Complements: make tens, then adjust

37 + 48  →  37 + 50 − 2 = 85

Adding awkward numbers is easier through the nearest round number. Subtraction too: 63 − 29 → 63 − 30 + 1 = 34. In Enigma this shines in the additive tail of an equation, where you're adjusting a big product toward the target.

Divisibility rules: spot exact divisions instantly

Because Enigma divisions must be exact, these four rules identify valid pairs at a glance:

Scan the bank with these before touching a ÷ slot and the decoys eliminate themselves.

Chunking: never carry more than one number

Long expressions overload working memory. Instead of holding every intermediate value, collapse as you go: in 4 × 6 − 8 + 3, think "24… 16… 19" — one running number, never the whole history. Combined with the two-tier precedence sweep, chunking is what makes a four-operator puzzle feel like three easy steps instead of one hard one.

Practice loop

Free play mode is the gym: pick a level slightly above comfortable, use the tricks deliberately (even when the direct calculation feels doable), and the shortcuts become automatic within a week or two of daily puzzles. Your streak — and your share-card times — will show it.

Play now →