burger fun / Four Fours / Solver

Make 47 with four 4s

The classic four fours puzzle: build an expression from exactly four 4s that equals 47. 47 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 4s and + - × ÷ reaches 47 — the solver checked every possible expression.

Solutions with concatenation and decimals

Concatenation and decimals do not help for 47 either — every combination was checked.

Solutions with square roots, factorials, exponents

  • 4! + 4! - 4 / 4 = 47
  • 4! + 4! - .4 / .4 = 47
  • 4! + 4! - 4! / 4! = 47
  • 4! - (4 / 4 - 4!) = 47
  • 4! + 4! - (4 - 4)! = 47

…and 21 more at this tier.

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

How 47 compares

47 has 26 distinct solutions across all three tiers — #29 scarcest of the 95 solvable targets. Next door, 46 has 157 solutions and 48 has 1,383 solutions. The nearest impossible target is 73, 26 away — proven unreachable, not just unsolved.

If 47 went down easily, make 43 with four 4s — 11 solutions, the nearest step up in scarcity.

Make 46 with four 4s · Make 48 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.