Becca had 13/15 of a yard of ribbon to use for her crafts projects. She used 3/7 of a yard to make a bow. How much ribbon, r, does Becca have left?

Answer 1

To find out how much ribbon Becca has left, we need to subtract the amount she used to make the bow from the total amount she had:

r = 13/15 - 3/7

To subtract these fractions, we need to find a common denominator. The smallest number that both 15 and 7 divide into is 105, so we'll use that:

r = (13/15) * (7/7) - (3/7) * (15/15)
r = 91/105 - 45/105

Now we can subtract the numerators:

r = (91 - 45)/105
r = 46/105

So Becca has 46/105 of a yard of ribbon left for her other crafts projects.