burger fun / Four Fours / Solver
Make 79 with four 4s
The classic four fours puzzle: build an expression from exactly four 4s that equals 79. 79 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 79 — the solver checked every possible expression.
Solutions with concatenation and decimals
Concatenation and decimals do not help for 79 either — every combination was checked.
Solutions with square roots, factorials, exponents
(4! - sqrt(4)) / .4 + 4! = 794! - (sqrt(4) - 4!) / .4 = 79
2 distinct solutions found in total, after removing trivial rearrangements.
Make 78 with four 4s · Make 80 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.