1 1/4 + 3/8 =

1. Convert 1 1/4 to an improper fraction: (1*4 + 1)/4 = 5/4.
2. Find a common denominator for 5/4 and 3/8, which is 8. Convert 5/4 to 10/8.
3. Add the fractions: 10/8 + 3/8 = 13/8. Convert back to a mixed number: 1 5/8.