7. Addition and Subtraction of Fractions
Recall that to add or subtract fractions, we need to have the same denominator.
Example 1:
Here, the lowest common denominator which we can use is 15. So we have:
Subtraction works in the same way...
Example 2:
Our lowest common denominator this time is 14. So we have:
When we have algebra using fractions, use the same rules.
Example 1:
The lowest common denominator here will be 6y4.
So we have:
We can write this as:
Example 2:
We factor the first denominator to get an idea of what to do:
We can see now that if we multiply the second fraction by 2x2, we will have a common denominator:
We would normally write this as:
Exercises. Simplify:
(1) 
(2) 
(3) 
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