Answer: 2 1/8 pounds of apples were left to give his grandmother.
Explanation:
He picked a total of 8 1/4 pounds. Converting 8 1/4 pounds to improper fraction, it becomes 33/4 pounds.
He took 3 3/4 pounds to his aunt. Converting 3 3/4 pounds to improper fraction, it becomes 15/4 pounds.
He also took 2 3/8 to his mother. Converting 2 3/8 pounds to improper fraction, it becomes 19/8 pounds.
The total number of apples that he gave to his aunt and mother is
15/4 + 19/8 = 49/8 pounds
The number of pounds of apples left to give his grandmother is
33/4 - 49/8 = 17/8 = 2 1/8 pounds