What is the difference in length between a 1 1/4 inch and a 3/8 inch?

Question

Can someone please answer?.. My younger sis needs help and her math is "wording" it so complicated.

I know the stuff with fractions but her mathbook is cursed 😭

Answer 1

Getting conmon denominators

1 1/4

5 / 4

10 / 8

10/8 - 3/8 = 7 / 8

Answer 2

Finding a difference means that you would compare the two measures. You could use a bar model for this to help your sister see that 1 1/4 inches is longer than 3/8 inches. Then you can explain to your sister that it would take 5 more 8ths (5/8) to get to 1 whole. Then you can add the 1/4 by finding the equivalent fraction 2/8 and adding it to the 5/8. It's a more round about approach, but the foundations of fraction concepts would be practiced. :)