Y5 maths. What are 'factors'?

[gaussgirl]

DS1 has just come home with his maths homework. He has 'factor spiders', a circle with a number in the middle and 8 legs. He has to write 'the factors' at the end of each leg. He says he knows what he's doing but I don't!

Factors....numbers that can be multiplied to make number in middle of the 'spider'!

So..2x10=20, 4x5=20 therefore 2,4,5,10 are factors of 20.

Is 1 a factor? and 20?

yes 1 and 20 would be too.

Agree with Liz. The only time 1 and,say, 11 would not be counted is when you're talking about prime numbers!

Oh OK. Numbers that have no factors apart from themselves and 1.

Factors are any numbers that will go into another number without leaving a remainder -

so factors of 8 are 1, 2, 4, 8

factors of 20 are 1, 2, 4, 5, 10, 20

factors of 7 are 1, 7 (this means it's a prime number)