Question

What is 3/5 plus 3/8

Answer 1

First I have to find the LCD And I got 24/40 & 15/40 Then when I got that I added both together and I got 30/40

Answer 2

Every time you want to add 2 fractions, they need to have the same denominator. 
Since 8 and 5 are not factors of the same number, you multiply 3/5 by 8, and 3/8 by 5. So you get:
$\frac{3*8}{5*8} + \frac{3*5}{8*5}$
$\frac{24}{40} + \frac{15}{40}$
$\frac{24+15}{40}$
$\frac{39}{40}$

Hope this Helps! :D