2 3/5 - 1 3/8 estimate
1 9/40 first you make the denominated 40 Then you multiply the same number you used to multiply the denominator Then subtract
2 3/5 - 1 3/8estimate : 3 - 1 = 2actual :2 3/5 - 1 3/8 =13/5 - 11/8 =104/40 - 55/40 =49/40 = 1 9/40