A recipe calls for a total of 3 2/3 cup flour and sugar. if the recipe calls for 1/4 cups of sugar, how much flour does he need

You'll want to convert 3 2/3 into a common denominator with 1/4.

The nearest common denominator of 3 and 4 is 12.

1/4 * 3/3 = 3/12

2/3 * 4/4 = 8/12

You need 3 and 8/12 in total so subtract 3/12 from 3 8/12 to get the flour

3 8/12 - 3/12 = 3 5/12.

You would need 3 5/12 cups of flour.