2/3+2/3=4/3 so = 1 1/3 cups

1 1/3 cup of sugar let me explain.2/3 cups plus 2/3 cup equals 4/3 cups. 4 divided by 3 equals 1 with 1 left over make 1 1/3.

1 and 1/3 cup..

1 1/3