Answer:
3 5/12 cups of flour are needed
Step-by-step explanation:
The flour-sugar total is 3 2/3 cups, of which 1/4 cup is sugar. Â So, to find the amount of flour used, we subtract 1/4 cup (sugar) from the total (3 2/3 cups):
 11    1
----- - ---- Â Â Â Â Â Â Â where 11/3 is the improper fraction form of 3 2/3
  3    4
The LCD is 12. Â Rewriting this subtraction using the LCD, we get:
44 Â Â 3
---- - ----- = 41/12 (cups) = 3 5/12 cups
12 Â Â 12
3 5/12 cups of flour are needed