Hard · Worked puzzle
Three factors, one small subtraction
Organise a four-blank puzzle by product and avoid counting rearrangements.
□ × □ × □ − □ = 74
5 distinct solutions · 4 blanks
Play this puzzleTry the board first, or open the hints below at your own pace. No answers are shown until you choose to reveal them.
Before you play
- Each blank takes one digit from 0 to 9. Choices may be repeated.
- Follow the printed brackets and the order of operations. Each division must be exact. Division by zero is never allowed.
- Find all 5 distinct solutions. Reordering terms of the same addition or multiplication counts once. Subtraction, division and bracket structure still matter.
- Play without an account. Progress stays in this browser; the Lobby’s Continue button resumes an unfinished game. Web Hint and Reveal are free.
Show a starting hint
Before the subtraction, the product must be between seventy-four and eighty-three.
Read the worked approach
- Write abc = 74 + d. The final digit limits the product to the interval 74–83. Zero cannot appear among the three factors because the product is positive.
- Only 75, 80 and 81 in this interval split into three factors from one to nine. The other candidates contain a prime factor larger than nine.
- For 75 use 3 × 5 × 5 and subtract 1. For 80 use 2 × 5 × 8 or 4 × 4 × 5 and subtract 6. For 81 use 1 × 9 × 9 or 3 × 3 × 9 and subtract 7.
- There are five unordered triples. Putting the same triple in a different order repeats a multiplication, so Mathoji keeps it as the same solution.
A common trap
Do not forget one as a factor. The triple 1, 9, 9 is as valid as a triple with three larger factors.
Carry this idea to the next puzzle
For a chain of multiplications, list sorted factor triples. This makes a four-blank puzzle manageable.
Reveal all 5 solutions
One representative of each distinct solution is shown. Other accepted orders of the same addition or multiplication are not repeated.
- 9 × 9 × 1 − 7 = 74
- 8 × 5 × 2 − 6 = 74
- 9 × 3 × 3 − 7 = 74
- 5 × 5 × 3 − 1 = 74
- 5 × 4 × 4 − 6 = 74
Check one answer, step by step
9 × 9 × 1 − 7 = 74
- 9 × 9 = 81
- 81 × 1 = 81
- 81 − 7 = 74