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.

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.

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

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