What is 45 and 1 4th plus 125 and 3 5ths?

Answer 1

When working with mixed numbers, it is usually easier to convert them to improper fractions, do the operations, and then to convert any resulting improper fraction back to a mixed number. However, due to the size of the whole numbers, in this case it is easier to add the fractions first, and then add the whole numbers to the result of that sum:

1/4 + 3/5 = (1×5)/(4×5) + (3×4)/(5×4) = 5/20 + 12/20 = (5+12)/20 = 17/20

→ 45 1/4 + 125 3/5 = 45 + 1/4 + 123 + 3/5 = 45 + 125 + (1/4 + 3/5) = 170 + 17/20 = 170 17/20.