Prime Factors

Every whole number greater than 1 can be written as a product of primes, and in only one way. This NSW Year 7 maths subtopic (NESA outcome MA4‑IND‑C‑01) teaches prime factorisation, the key that unlocks the HCF, the LCM and some square roots.

You will build factor trees, use repeated division by the smallest prime, write the result in index form such as \(180 = 2^2 \times 3^2 \times 5\), rebuild a number from its prime factors, and find the smallest multiplier that makes a square number. The same idea sits behind the codes that keep online payments safe. It is part of Year 7 Whole Numbers.