Noah made 1 1/2 dozen blueberry muffins and 1 3/4 dozen lemon muffins. He needs to take 5 dozen muffins to the bake sale. How many dozen more muffins does he need to bake?

Convert to improper fraction first

1 1/2 = 3/2

1 3/4 = 7/4

convert 3/2 into quarters = 6/4

Then add together 6/4 + 7/4 = 13/4

Convert back into mixed number 3 1/4 so to make up to 5 muffins - 1 3/4 muffins are required