Which is the difference of 21 1/4 - 18 2/4

A 2 1/4 B 2 2/4 C 2 3/4 D 3 1/4

So when you change the mixed numbers into improper fractions, they become 85/4 and 74/4. Your new problem is 85/4-74/4. Basically 85-74. That equals 9. So the improper fraction answer is 9/4. We now make that back into a mixed number, creating 2 1/4, or A.