Question

Mr. Cheng is making shades for his office. One window needs 1 1/3 yards of material and the other window needs 1 3/4 yards of material. The fabric store only sells whole-number lengths of this material. How many yards of material should Mr. Cheng buy?

Answer 1

11/3 = 9 and 2/3
13/4 = 3 and 1/4

9+3 = 12

2/3 + 1/4 = 8/12 +3/12
which is 11/12
in total he needs 12 and 11/12 yards
So he needs to buy 13 yards of shades.