burger fun / Four Nines / Solver
Make 87 with four 9s
The classic four nines puzzle: build an expression from exactly four 9s that equals 87. 87 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 87 — the solver checked every possible expression.
Solutions with concatenation and decimals
Concatenation and decimals do not help for 87 either — every combination was checked.
Solutions with square roots, factorials, exponents
99 - 9 - sqrt(9) = 8799 - sqrt(9) - 9 = 879 × 9 + 9 - sqrt(9) = 879 + 9 × 9 - sqrt(9) = 879 × 9 / .9 - sqrt(9) = 87
…and 40 more at this tier.
45 distinct solutions found in total, after removing trivial rearrangements.
How 87 compares
87 has 45 distinct solutions across all three tiers — #47 most plentiful of all 100 targets. Next door, 86 has 31 solutions and 88 has 2 solutions.
If 87 went down easily, make 88 with four 9s — 2 solutions, the nearest step up in scarcity.
Make 86 with four 9s · Make 88 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
- Four Fours — the 1881 original
- Four Fours solver — including the impossible five
- Make 24 solver — any four digits
- Today's 24 — one new hand a day
Got what you came for?
Stay for something you did not search for.
- Four Nines — the daily puzzle: four 9s, one target, new at midnight
- The Reflex Lab — nine ways to measure your hands and memory, none of them polite about it
- hand me something weird — a random pick from the directory. Could be the horse.
Play the daily Four Nines puzzle, pick another number in the solver, or find more free math games.