burger fun / Four Fours / Solver

Make 17 with four 4s

The classic four fours puzzle: build an expression from exactly four 4s that equals 17. 17 can be made with nothing but four 4s, + - × ÷, and parentheses.

Solutions using only + - × ÷

  • 4 × 4 + 4 / 4 = 17

Solutions with concatenation and decimals

  • .4 / .4 + 4 × 4 = 17

Solutions with square roots, factorials, exponents

  • (4! + 44) / 4 = 17
  • 4! / 4! + 4 × 4 = 17
  • (4 - 4)! + 4 × 4 = 17
  • 4! - (4 + 4!) / 4 = 17
  • (.4 - .4)! + 4 × 4 = 17

…and 42 more at this tier.

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

How 17 compares

17 has 49 distinct solutions across all three tiers — #46 scarcest of the 95 solvable targets. Exactly one of them uses nothing but + - × ÷. Next door, 16 has 2,689 solutions and 18 has 351 solutions. The nearest impossible target is 73, 56 away — proven unreachable, not just unsolved.

If 17 went down easily, make 31 with four 4s — 9 solutions, the nearest step up in scarcity.

Make 16 with four 4s · Make 18 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.