Hello!
if you use 2 3/8 yards of fabric to make a costume, and need 7 costumes, multiply the amount of fabric needed by the amount of costumes needed
2 3/8 * 7 = 14 21/8
then simplify the fraction
21/8 = 2 5/8
add it to the whole number
14 + 2 5/8 = 16 5/8
you need 16 5/8 yards of fabric to make 7 dresses
I hope this helps, and have a nice day!