Number

Powers and square roots

A power is a short way to write the same number multiplied by itself many times. The square root goes back the other way: which number gave this square?

Lower secondary (years 1-2)Ages 12 to 14Draft: Not yet checked by a maths teacher.

What you need first

Negative numbers

Why

A square patio has an area of 49 m². How long is one side?

If you write out 2×2×2×2×2×2×2×2×2×2 in full, it is easy to count one factor too many or too few. With a power you simply write 2^{^10}.

And sometimes you already know the result and are looking for the number you started with. A square of 49 m² has sides of 7 m, because 7×7=49. That is the square root: √(49)=7.

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