Ah yes, adding fractions! Adding fractions can be a bit of a pain.
So, we have
.
To add fractions, the bottoms, or denominators, must be the same number. So we must multiply the fractions by certain numbers to make the denominators the same number. So let's go easy and make the denominator 40, because 8 goes into 40 and so does 5. So, to make 8 become 40, we'll multiply the whole fraction by 5. For 5, we'll multiply by 8.
Now we'll add the two fractions. When we add fractions we only add the tops, the numerators.
Then we must reduce (or try to reduce). This fraction cannot be reduced, so the answer is simply
.
I hope this helps you understand.
-Toremi