• Free
  • Grade 8
  • Squares to 625, cubes to 1728

Square roots and cube roots worksheets

A square root asks a question: which number, times itself, gives this one? These free printable worksheets evaluate perfect squares and perfect cubes, so every answer is a whole number.

Kid stuck on one? You don’t just get the sheet.

  • Answer key included
  • Reopen this exact sheet
  • Letter & A4 ready
Ready to printSquare roots and cube roots
Square roots and cube roots worksheet — Squares to 625, cubes to 1728, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

The error worth designing against is not arithmetic. Handed √324, a child who has known the symbol for a week divides — 324 ÷ 2 = 162 — because a radical looks like an operator that does something TO the number. Every sheet here is built so the question can be re-read as a question, and the step-by-step walk opens by doing exactly that.

Why this sheet works

The mixed setting is the one worth choosing, and it exists for a single reliable mistake: reading ∛ as √. A page of square roots never tests whether a child checks the symbol, because there is nothing to check. A page that alternates them does, and it is the only page that does.

How this one works

One question from this sheet, worked through a step at a time.

√289

√289=
10²=100— under
20²=400— over
√289is between10 and 20
√289=13 or 17
√289=17
17 × 17=289
√289=17
  1. √ asks a question: which number times itself gives 289? It is not an instruction to halve 289 — that is the mistake this symbol collects.
  2. Bracket it first. 10² = 100, which is under 289, and 20² = 400, which is over. So the answer is between 10 and 20.
  3. Now the last digit. 289 ends in 9, and the only digits whose square ends in 9 are 3 and 7. Between 10 and 20 that leaves 13 or 17.
  4. Two left, and the bracket picks between them: 289 is nearer 400 than 100, so take the bigger one — 17.
  5. Check it: 17 × 17 = 289. So √289 = 17.