# 7. Addition and Subtraction of Fractions

Recall that to add or subtract fractions, we need to have the same denominator.

### Example 1

Add the fractions: 2/3+4/15

Solution: Here, the lowest common denominator which we can use is 15. So we have:

2/3+4/15=10/15+4/15=14/15

Subtraction works in the same way, as we see in the next example.

6/7-5/14

### Example 3

a/(6y)-(2b)/(3y^4)

### Example 4

(x-1)/(2x^3-4x^2)+5/(x-2)

Continues below

### Exercises

Simplify the following.

(1) 2/(s^2)+3/s

(2) 5+(1-x)/2-(3+x)/4

(3) 5/(6y+3)-a/(8y+4)

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