Make 12 with four 9s

The classic four nines puzzle: build an expression from exactly four 9s that equals 12. 12 cannot be made with + - × ÷ alone (the solver checked every expression) — you will need to stick 9s together (like 99) or use decimals (like .9).

Solutions using only + - × ÷

No expression made of four plain 9s and + - × ÷ reaches 12 — the solver checked every possible expression.

Solutions with concatenation and decimals

(9 + 99) / 9 = 12
(.9 + 9.9) / .9 = 12
(.9 + .9 + 9) / .9 = 12

Solutions with square roots, factorials, exponents

9 × 9 / 9 + sqrt(9) = 12
9 + 9 × sqrt(9) / 9 = 12
9 + 9 + sqrt(9) - 9 = 12
9 + 9 - 9 + sqrt(9) = 12
9 + 9 / 9 × sqrt(9) = 12

…and 1173 more at this tier.

1181 distinct solutions found in total, after removing trivial rearrangements.

Make 11 with four 9s · Make 13 with four 9s

The Number Lab

Same idea, different constraints: four 9s, four 4s, or any four digits you like.

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Play the daily Four Nines puzzle, pick another number in the solver, or find more free math games.