Factors and multiples
Factors divide into a number; multiples come out of it.
A factor of a whole number is any number that divides into it exactly, with no remainder. The factors of are and . Notice they come in pairs that multiply to give 12: , , .
A multiple of a number is what you get when you multiply it by a whole number. The multiples of are — they go on for ever.
The neat trick for finding all the factors of a number is to list pairs going up from . For : , , , , . Stop when the two numbers in the pair meet (here at ). The full list is .
- Factors divide a number exactly; multiples are products of it.
- Factors come in pairs that multiply to the original number.
- Stop listing factor pairs when the two values meet.
- Multiples of a number continue without end.