Question from a parent helping a child, grade 4, with homework. Can a number have three factors? Name three numbers that have three factors.

Hi,
Any integer greater than 1 has at least 2 factors since the number itself and 1 are factors. For example 6 has 6 and 1 as factors. But 2 and 3 are also factors of 6 since 6 = 2x3. Thus 6 has 4 factors.

Factors come in pairs. For 6 above the pairs are 6 and 1 since 6 = 6x1, and 2 and 3 since 6 = 2x3. If you are looking for a number m with exactly 3 factors then an example would be 4 where the factors are 4 and 1 (4 = 4x1) and 2 (4 = 2x2). Another example is 9 since 9 = 3x3. The numbers with exactly three factors are squares, but not all squares work. You should now be able to find a third such number, and maybe a fourth and fifth.

Cheers,
Penny
Go to Math Central