burger fun / Four Nines / Solver

Make 2 with four 9s

The classic four nines puzzle: build an expression from exactly four 9s that equals 2. 2 can be made with nothing but four 9s, + - × ÷, and parentheses.

Solutions using only + - × ÷

  • 9 / 9 + 9 / 9 = 2

Solutions with concatenation and decimals

  • 99 / 9 - 9 = 2
  • .9 + 9.9 / 9 = 2
  • 9.9 / .9 - 9 = 2
  • .9 + .99 / .9 = 2
  • .9 / .9 + 9 / 9 = 2

…and 3 more at this tier.

Solutions with square roots, factorials, exponents

  • 9! / 9! + 9 / 9 = 2
  • (9 - 9)! + 9 / 9 = 2
  • .9 / .9 + 9! / 9! = 2
  • 9! / 9! + 9! / 9! = 2
  • (.9 - .9)! + 9 / 9 = 2

…and 2087 more at this tier.

2101 distinct solutions found in total, after removing trivial rearrangements.

How 2 compares

2 has 2,101 distinct solutions across all three tiers — #6 most plentiful of all 100 targets. Exactly one of them uses nothing but + - × ÷. Next door, 1 has 13,973 solutions and 3 has 6,307 solutions.

If 2 went down easily, make 4 with four 9s — 722 solutions, the nearest step up in scarcity.

Make 1 with four 9s · Make 3 with four 9s

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 puzzle: 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.

Play the daily Four Nines puzzle, pick another number in the solver, or find more free math games.