Lesson 3: Adding and subtracting fractions (unlike denominators)
Here is a PDF version of the lesson.
Here is a PDF version of the workbook containing lots of practice.
In order to add or subtract two fractions it is important to represent them as a part of the same whole. Thus, their denominator must be the same.
If two fractions with different denominators are being added or subtracted, first bring them to the Lowest Common Denominator by determining their Least Common Multiple.
For example, for denominators 2 and 5, the Lowest Common Denominator is 10 – the lowest number divisible by both given denominators.
For mixed numbers, first convert the mixed numbers into improper fractions and then follow the steps above.