Make 98 with four 9s

The classic four nines puzzle: build an expression from exactly four 9s that equals 98. 98 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 98 — the solver checked every possible expression.

Solutions with concatenation and decimals

99 - 9 / 9 = 98
99 - .9 / .9 = 98

Solutions with square roots, factorials, exponents

99 - 9! / 9! = 98
99 - (9 - 9)! = 98
99 - (.9 - .9)! = 98
99 - (9! - 9!)! = 98
9 + 9 + sqrt(9)!! / 9 = 98

…and 7 more at this tier.

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

Make 97 with four 9s · Make 99 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.