In order to reduce ANY fraction to lowest terms, find any common factors
of the numerator and denominator, and divide them both by it. If they still
have a common factor, then divide them by it again. Eventually, they won't
have any common factor except ' 1 ', and then you'll know that the fraction is
in lowest terms.
Do 15 and 40 have any common factors ?
Let's see . . .
The factors of 15 are 1, 3, 5, and 15 .
The factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40 .
Ah hah ! Do you see that ' 5 ' on both lists ? That's a common factor.
So 15/40 is NOT in lowest terms.
Divide the numerator and denominator both by 5 :
15 / 40 = 3 / 8
3 and 8 don't have any common factor except ' 1 '.
So 3/8 is the same number as 15/40, but in lowest terms.