1.6 Square roots and cube roots · Unit 1 Integers

1 · Teaching slidesuse ← → keys

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2 · Key words

square numberThe number you get when you multiply an integer by itself, such as 25 = 5 × 5.

square rootThe number that was multiplied by itself; √25 = 5.

cube numberThe number you get when you multiply an integer by itself and then by itself again, such as 27 = 3 × 3 × 3.

cube rootThe number that was cubed; ∛27 = 3.

indexThe small raised number showing the power, as in 7² or 4³.

estimateTo find an approximate value, close enough to be useful.

3 · Summary of the sectionrevise from this

Square numbers: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, …
Cube numbers: 1, 8, 27, 64, 125, 216, 343, 512, 729, 1000, …
√ undoes squaring, and ∛ undoes cubing — they are inverse operations.
√144 = 12 because 12² = 144; ∛125 = 5 because 5³ = 125.
To estimate √n when n is not a square number, find the square numbers either side of it: 49 < 50 < 64, so 7 < √50 < 8.
64 is special — it is both a square number (8²) and a cube number (4³).

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