burger fun / Four Fours / Solver
Make 55 with four 4s
The classic four fours puzzle: build an expression from exactly four 4s that equals 55. 55 cannot be made with + - × ÷ alone (the solver checked every expression) — you will need to stick 4s together (like 44) or use decimals (like .4).
Solutions using only + - × ÷
No expression made of four plain 4s and + - × ÷ reaches 55 — the solver checked every possible expression.
Solutions with concatenation and decimals
44 / (.4 + .4) = 55
Solutions with square roots, factorials, exponents
(4! - .4) / .4 - 4 = 5544 / .4 / sqrt(4) = 5544 / sqrt(4) / .4 = 5544 / (.4 × sqrt(4)) = 554! / .4 - sqrt(4) / .4 = 55
…and 33 more at this tier.
39 distinct solutions found in total, after removing trivial rearrangements.
How 55 compares
55 has 39 distinct solutions across all three tiers — #38 scarcest of the 95 solvable targets. Next door, 54 has 29 solutions and 56 has 102 solutions. The nearest impossible target is 73, 18 away — proven unreachable, not just unsolved.
If 55 went down easily, make 53 with four 4s — 3 solutions, the nearest step up in scarcity.
Make 54 with four 4s · Make 56 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.