burger fun / Four Fours / Solver
Make 70 with four 4s
The classic four fours puzzle: build an expression from exactly four 4s that equals 70. 70 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 70 — the solver checked every possible expression.
Solutions with concatenation and decimals
Concatenation and decimals do not help for 70 either — every combination was checked.
Solutions with square roots, factorials, exponents
(4! + 4 ^ 4) / 4 = 704! / .4 + 4 / .4 = 70(4 + 4)! / 4! / 4! = 704! + 44 + sqrt(4) = 704! + sqrt(4) + 44 = 70
…and 42 more at this tier.
47 distinct solutions found in total, after removing trivial rearrangements.
How 70 compares
70 has 47 distinct solutions across all three tiers — #43 scarcest of the 95 solvable targets. Next door, 69 has 5 solutions and 71 has 3 solutions. The nearest impossible target is 73, 3 away — proven unreachable, not just unsolved.
If 70 went down easily, make 69 with four 4s — 5 solutions, the nearest step up in scarcity.
Make 69 with four 4s · Make 71 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
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.