i know this because if you double the denominator of 1/4 from 4 to 8 you'll also have to do that with the numerator so the 1 will turn into a 2 so you'll have 2/8 so then you add 2/8 and 3/8 and you get 5/8 but we need to know what fraction part is green so you subtract 5/8 from 8/8 and get 3/8
