Explanation:
Stefan has 4½ cups of oat
He uses 3¼ to make granola
What he has left 4½-3¼ = 1¼
If he feeds ¼of a cup to parrots a day, then he has 5 days feed from 1¼
Calculation 1¼ ÷ ¼
Change to improper fraction
5/4 ÷ 1/4 = 5/4 x 4/1
Ans 20/4 = 5days