Math (Check
posted by Bryan .
Subtract and Simplify
2/3  1/5 = 1/2

Not quite.
The common denominator 15 (the smallest number divisible by both 3 and 5).
Since 15 divided by 3 is 5, then you multiply the numerator by 5.
Since 15 divided by 5 is 3, then you multiply the numerator by 3.
2/3  1/5 = 10/15  3/15 = 7/15