Solving Proportions with Cross Multiplication

Math with Mr. J

This instructional video serves as a clear, step-by-step tutorial on solving proportions using the cross-multiplication method. Narrated by 'Mr. J,' the video guides viewers through four distinct practice problems, each featuring a missing value represented by a different variable (n, x, m, w). The content focuses on the procedural mechanics of setting up the cross products and solving the resulting one-step linear equations to find the unknown terms. The key themes explored include the definition of proportions as equivalent ratios, the algebraic technique of cross multiplication, and the fundamentals of solving one-step equations using inverse operations. The video reinforces the concept that the product of the means equals the product of the extremes, visualising this process by drawing 'X' shaped arrows across the equal sign to guide the multiplication. For educators, this video is an excellent resource for direct instruction, review, or remediation in middle school math classrooms. It breaks down the abstract concept of solving for a variable into a repeatable, visual process. Teachers can use this video to flip the classroom, assigning it as homework before a lesson on ratios, or as a support tool for students who need extra practice with the algorithm of cross multiplication.