Mary H. answered • 02/09/18

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The smallest common denominator has to be as big as the biggest denominator, so we are looking at 20. 1/5 needs to be changed:what number can we multiply 5 by to get 20? Well, 20/5 is 4, so 5 times 4 is twenty. You multiply both the numerator and denominator by 4, and get 1/5 = 4/20. 1 is a whole, so it is 20/20. The fractions are now 1/20,4/20. 7/20 and 20/20,

The largest two, then, are found by the ones that have the most twentieths, so they are 20/20 and 7/20. I want to subtract the two fractions. Since the denominators are the same, I just subtract the numerators.

20-7 = 13

20 20

Hope that helped! Keep working and remember to breathe!