Question

Evie is trying to add together 13/25 and 4/15 her first step is to rewrite the fractions using their lowest common denominator. What denominator should she use?

Answer 1

75

Explanation:

I would suggest starting by finding the first five multiples of 15 and then 25

multiples of 15 are: 15, 30, 45, 60, 75

multiples of 25 are: 25, 50, 75, 100, 125

compare each list to see if you have any in common and select the lowest; in this case 75

*if you didn't have anything in common then keep adding multiples to the lists

see how many times you must multiply each denominator by to get 75

15 x 5 = 75

25 x 3 = 75

so now you can multiply 13/25 by 3 to get 39/75

and multiply 4/15 by 5 to get 20/75

as long as the denominators are the same, add the numerators and keep the denominator

sum would be 59/75