Question

How do I solve 2 1/4 of lemonade and drinks 2/5 of a cup. How much is left?

Answer 1

If your question means:

I have 2 1/4 cups of lemonade and I drank 2/5 cups. How much is left?

then

2 1/4 = 2 + 1 / 4 = 2 ∙ 4 / 4 + 1 / 4 = 8 / 4 + 1 / 4 = 9 / 4

2 1/4 - 2 / 5 = 9 / 4 - 2 / 5 = 5 ∙ 9 / 5 ∙ 4 - 4 ∙ 2 / 4 ∙ 5 = 45 / 20 - 8 / 20 =

37 / 20 = ( 20 + 17 ) / 20 = 20 / 20 + 17 / 20 = 1 17/20