burger fun / Four Nines / Solver

Make 29 with four 9s

The classic four nines puzzle: build an expression from exactly four 9s that equals 29. 29 cannot be made with + - × ÷ alone (the solver checked every expression) — you will need to stick 9s together (like 99) or use decimals (like .9).

Solutions using only + - × ÷

No expression made of four plain 9s and + - × ÷ reaches 29 — the solver checked every possible expression.

Solutions with concatenation and decimals

  • (9 + 9) / .9 + 9 = 29

Solutions with square roots, factorials, exponents

  • (9 × sqrt(9) - .9) / .9 = 29
  • 9 + sqrt(9)! × sqrt(9) / .9 = 29
  • 9 + sqrt(9) × sqrt(9)! / .9 = 29
  • (9 × 9 + sqrt(9)!) / sqrt(9) = 29
  • (9 + sqrt(9)! / 9) × sqrt(9) = 29

…and 18 more at this tier.

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

Make 28 with four 9s · Make 30 with four 9s

The Number Lab

Same idea, different constraints: four 9s, four 4s, or any four digits you like.

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