Make 47 with four 9s

The classic four nines puzzle: build an expression from exactly four 9s that equals 47. 47 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 47 — the solver checked every possible expression.

Solutions with concatenation and decimals

Concatenation and decimals do not help for 47 either — every combination was checked.

Solutions with square roots, factorials, exponents

9! / 9 / sqrt(9)!! - 9 = 47
9! / sqrt(9)!! / 9 - 9 = 47
9! / (9 × sqrt(9)!!) - 9 = 47
(9 + sqrt(9)! / .9) × sqrt(9) = 47

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

Make 46 with four 9s · Make 48 with four 9s

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