What is a common factor?

A factor is a number that can be multiplied into another number with nothing left over. The factors of 9 are 1, 3, 9.A common factor is a number that is a factor of two different numbers. The factors of 9 are 1,3, 9 and the factors of 12 are 1, 2, 3, 4, 6, 12. The common factors are the numbers that appear in both lists. so here, the common factors are 1 and 3.

TH

Related Maths KS3 answers

All answers ▸

What is the Pythagoras’ theorem and how can it be used to work out the distance between two points?


Anton, Barbara and Clive are buying pens from the shop. Anton needs 4, Barbara needs 7, Clive needs 11. Pens only come in packs of 10. How many packs of pens do they need to buy between them?


A triangle has the following dimensions: 5 km, 12 km and 13 m. Is it a right triangle?


1) What is the area of a rectangle? 2) What is the area of a triangle?