If you would like to know how many dozens of muffins were baked for a bake sale in all, you can calculate this using the following step:
21/3 dozen carrot muffins + 1 3/4 dozen apple muffins = 21/3 + 7/4 = 84/12 + 21/12 = 105/12 = 35/4 = 8 3/4 dozens of muffins
The correct result would be 8 3/4 dozens of muffins.
