burger fun / Four Fours / Solver
Make 87 with four 4s
The classic four fours puzzle: build an expression from exactly four 4s that equals 87. 87 cannot be made from four 4s at all under these rules — tiers 1 and 2 are proven exhaustively, and the bounded tier-3 search came up empty too.
Solutions using only + - × ÷
No expression made of four plain 4s 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
No solution found at this tier within the solver’s search bounds — square roots, factorials, and exponents all come up empty.
Zero solutions found. Not for lack of trying — the solver tried everything its rules allow.
How 87 compares
87 is one of only 5 targets out of 100 that four 4s cannot reach — the full list is 73, 77, 87, 93, 99. Next door, 86 has 7 solutions and 88 has 83 solutions.
The nearest fellow holdout is 93, also proven impossible.
Make 86 with four 4s · Make 88 with four 4s
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 sibling: 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.
Read up on the 1881 original, pick another number in the solver, or find more free math games.