Here's another method - useful when the denominators have no factors in common....like this one....
7/8 + 3/5
Cross-multiply the 7 and 5 = 35
Cross multiply the 5 and 8 = 40
Write these,in order, with the same sign (a plus) between them as in the original problem.....so we have
35 + 40
Add these = 59 (1)
Multiply the original denominators = 8 * 5 = 40 (2)
Put (1) over (2) =
59 / 40
