Master · Worked puzzle
Three ways for a root product to make two
A square root can combine with another root to give a whole-number result.
√(□) × □ + □ × 5 = 12
3 distinct solutions · 3 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 accepts one of these complete expressions: 012341/21/32/33/2√2√3∛2. Choices may be repeated.
- Follow the printed brackets and the order of operations. Fractional intermediate values are allowed. Division by zero is never allowed.
- Find all 3 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
Try two in the last blank. What must the first part contribute to twelve?
Read the worked approach
- With two in the last blank, the final term is 2 × 5 = 10. The root product must supply the remaining two.
- One way is √1 × 2 = 2. Another is √4 × 1 = 2. Both roots simplify to whole numbers before the multiplication.
- A third way is √2 × √2 = 2. Put 2 inside the printed root and choose √2 for the next blank. Two identical positive square roots multiply to their radicand.
- The exhaustive check of this puzzle’s allowed keypad choices yields these three distinct solutions. They have the same numerical result but different root-and-operand structures, so each earns a separate row.
A common trap
The first blank already sits inside a square-root symbol. Choosing √2 there would create √(√2), not √2.
Carry this idea to the next puzzle
Read the printed operators before choosing an expression key. A whole-number answer can come from irrational intermediate values.
Reveal all 3 solutions
One representative of each distinct solution is shown. Other accepted orders of the same addition or multiplication are not repeated.
- √(1) × 2 + 2 × 5 = 12
- √(2) × (√2) + 2 × 5 = 12
- √(4) × 1 + 2 × 5 = 12
Check one answer, step by step
√(1) × 2 + 2 × 5 = 12
- 1 × 2 = 2
- 2 × 5 = 10
- 2 + 10 = 12
The step check shows decimal approximations where needed; fraction and root keys above retain their exact written form.