Answer:
1/4 of a yard of material
Explanation:
First, we must convert both 12 1/4 yards and 8 1/2 yards to quarters. Since 1/2 of a yard is equal to 2/4 of a yard, 8 1/2 yards will be equal to 8 2/4 yards. 8 yards + 12 yards = 20 yards, and 2/4 of a yard + 1/4 of a yard = 3/4 of a yard, so you get 20 3/4 of a yard to finish the draperies. To find the leftover material, do 21 yards - 20 3/4 yards = 1/4 of a yard of material. Hope this helps!