Make 10 with four 4s

The classic four fours puzzle: build an expression from exactly four 4s that equals 10. 10 cannot be made with + - × ÷ alone (the solver checked every expression) — you will need to stick 4s together (like 44) or use decimals (like .4).

Solutions using only + - × ÷

No expression made of four plain 4s and + - × ÷ reaches 10 — the solver checked every possible expression.

Solutions with concatenation and decimals

44 / 4.4 = 10
4.4 / .44 = 10
(44 - 4) / 4 = 10
4 × 4 / .4 / 4 = 10
4 × 4 / 4 / .4 = 10

…and 49 more at this tier.

Solutions with square roots, factorials, exponents

4 × 4 - 4! / 4 = 10
4! - 4 - 4 / .4 = 10
4! - 4 / .4 - 4 = 10
(4! + 4 × 4) / 4 = 10
(4 - 4 / 4)! + 4 = 10

…and 848 more at this tier.

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

Make 9 with four 4s · Make 11 with four 4s

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

Read up on the 1881 original, pick another number in the solver, or find more free math games.