burger fun / Four Fours / Solver

Make 12 with four 4s

The classic four fours puzzle: build an expression from exactly four 4s that equals 12. 12 can be made with nothing but four 4s, + - × ÷, and parentheses.

Solutions using only + - × ÷

  • 4 × (4 - 4 / 4) = 12

Solutions with concatenation and decimals

  • (4 + 44) / 4 = 12
  • (.4 + 4.4) / .4 = 12
  • 4 × (4 - .4 / .4) = 12
  • (.4 + .4 + 4) / .4 = 12

Solutions with square roots, factorials, exponents

  • 4! + 4 - 4 × 4 = 12
  • 4! - 4 - 4 - 4 = 12
  • 4 + 4! - 4 × 4 = 12
  • 4! / 4 + 4! / 4 = 12
  • 4! × 4 / (4 + 4) = 12

…and 1528 more at this tier.

1538 distinct solutions found in total, after removing trivial rearrangements.

How 12 compares

12 has 1,538 distinct solutions across all three tiers — #8 most plentiful of the 95 solvable targets. Exactly one of them uses nothing but + - × ÷. Next door, 11 has 129 solutions and 13 has 70 solutions. The nearest impossible target is 73, 61 away — proven unreachable, not just unsolved.

If 12 went down easily, make 11 with four 4s — 129 solutions, the nearest step up in scarcity.

Make 11 with four 4s · Make 13 with four 4s

The Number Lab

Same idea, different constraints: four 9s, four 4s, or any four digits you like.

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.