How to Add and Subtract Rational Expressions with Simple Denominators

Miacademy & MiaPrep Learning Channel

This instructional video guides students through the process of adding and subtracting rational expressions with simple denominators (monomials and binomials). The lesson begins by reviewing how to add standard numerical fractions, establishing a four-step framework that applies equally to algebraic expressions. This connection helps demystify the process by showing that the fundamental rules of mathematics remain consistent whether working with numbers or variables. The video progresses through four distinct examples increasing in complexity: adding with monomial denominators, subtracting with monomial denominators, adding with mixed monomial/binomial denominators, and finally subtracting with two binomial denominators. Key mathematical concepts covered include identifying the Least Common Multiple (LCM) to find common denominators, manipulating expressions by multiplying by 'one' (e.g., 4x/4x), and the critical importance of distributing negative signs during subtraction. For educators, this resource serves as an excellent direct instruction tool or review for Algebra students. It explicitly addresses common student errors, particularly the failure to distribute the subtraction sign across a binomial numerator. The video includes built-in pause points that allow for active participation, making it suitable for a flipped classroom model or whole-class guided practice where students attempt steps before the video reveals the solution.