Make 24 with four 9s

The classic four nines puzzle: build an expression from exactly four 9s that equals 24. 24 cannot be made with + - × ÷, concatenation, or decimals (the solver checked every expression) — solutions need square roots, factorials, or exponents.

Solutions using only + - × ÷

No expression made of four plain 9s and + - × ÷ reaches 24 — the solver checked every possible expression.

Solutions with concatenation and decimals

Concatenation and decimals do not help for 24 either — every combination was checked.

Solutions with square roots, factorials, exponents

99 / sqrt(9) - 9 = 24
9 + 9 + 9 - sqrt(9) = 24
(9 - 9 / (.9 + .9))! = 24
(9 × 9 - 9) / sqrt(9) = 24
(9 - 9 / 9) × sqrt(9) = 24

…and 1111 more at this tier.

1116 distinct solutions found in total, after removing trivial rearrangements.

Make 23 with four 9s · Make 25 with four 9s

The Number Lab

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

Four Nines — the daily puzzle
Four Nines solver — every target, solved
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Four Fours solver — including the impossible five
Make 24 solver — any four digits
Today's 24 — one new hand a day

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