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Perfect Squares, Cubes & Roots

5 min readGrade 8 · Number

Perfect squares, perfect cubes, and their roots extend students' number sense into new territory. They discover that 144 = 12 × 12 so √144 = 12, and that 125 = 5 × 5 × 5 so the cube root of 125 is 5 — these operations are inverses. Estimating √50 by locating it between √49 and √64 builds the number-line thinking that underpins all of real number work.

What students explore

Square roots and perfect squares extend students' number sense into a new territory. They discover that 144 = 12 × 12 and so √144 = 12 — squaring and square-rooting are inverses. Estimating √50 by locating it between √49 and √64 builds the number-line thinking that underpins all of real number work.

Key ideas

Identify perfect squares to 225. Determine the square root of a perfect square. Estimate the square root of a non-perfect square to the nearest tenth. Explain the relationship between squaring and taking a square root.

Putting it together

Apply these ideas through worked examples, guided practice, and real-world problems.

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