Explanation:
To make pancakes, Sheila needs 2 ½ cups of flour. If Sheila only has 2/3 cup of flour, how much more flour does she need?
2 1/2 cups = 5/2 cups
Sheila has 2/3 cup flour but needs 5/2 cups.
Make denominators equal to 6:
Sheila has 4/6 cup flour but needs 15/6 cups so the difference is:
15/6 - 4/6 = 11/6 cups or 1 5/6 cups