Question 847497
I will do this two different ways.

The common way is to find a common denominator:

What is the common denominator for 3 and 8?

Look at the multiples of 3 and 8

3,6,9,12,15,18,21,24,27,30
8,16,24

We find that 24 is the first common multiple, so it must be it.

So, we convert each fraction into a denominator of 24.

{{{1/3 =  (1*8)/(3*8) =  8/24}}}
{{{1/8 =  (1*3)/(8*3) = 3/24}}}

So adding this together gives us 11/24.

METHOD 2(cross multiply)

1/3 + 1/8  

Start in the left corner and multiply by it with its diagonal

1*8 = 8

Take the other diagonal and multiply together

3*1 = 3

Add those two together to get our numerator.

8+3 = 11

Take the denominators and multiply them together 

3*8 = 24

So our answer is (8+3)/24 = 11/24