In addition and subtraction the denominator must be the same.

You only add or subtract the numerator (the top number).
Never add or subtract the denominators (the bottom number).

When you borrow for subtraction, remember to reduce the whole number by one and add the denominator to the numerator giving you a new numerator quantity.

Therefore 4 1/4 becomes 3 5/4.

Never multiply with mixed numbers always change to an improper fraction.
EXAMPLE (3 1/2 = 7/2).

Think 2 x 3 = 6 + 1 = 7

7/2

Never divide with mixed numbers always change to an improper fraction.
EXAMPLE (3 1/2 = 7/2).

Think 2 x 3 = 6 + 1 = 7

7/2