Khan Academy: Adding & Subtracting Rational Expressions: Like Denominators

This instructional activity contains a good selection of problems of adding and subtracting rational expressions. There are eight problems. None of the problems have common denominators.  A few are mixed expressions and some require...

There's a fine line between a numerator and a denominator! Learners find common denominators in order to add and subtract rational expressions. Examples include addition, subtraction, and complex fractions.

Sal adds 6/(2x^2-7) + (-3x-8)/(2x^2-7) and subtracts (9x^2+3)/(14x^2-9) - (-3x^2+5)/(14x^2-9).

Check your understanding of how to add and subtract rational expressions that have like denominators with these problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive...

Add and subtract rational expressions with relatively prime denominators by manipulating them to have the same denominators.

Have you learned the basics of rational expression addition/subtraction? Great! Now dig deeper with some advanced examples.

Example: Add and simplify 6/(2x^2-7) + (-3x-8)/(2x^2-7).

Check your understanding of how to add and subtract rational expressions with these problems where the denominators have factors. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or...

Add and subtract rational expressions with relatively prime denominators by manipulating them to have the same denominators. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or...

Video shows example of adding and subtracting rational expressions. Includes discussion of using the least common multiple of the denominators for a common denominator. [2:56]