This is a beginner lesson for pre-algebra or 7th grade math — one-step equations that are solved by multiplying or dividing.
First, I explain how we simplify expressions such as 5x/5 (the fives cancel out). Then I show how to solve simple equations by either dividing or multiplying both sides by the same number, in order to isolate the unknown (leave it alone on one side of the equation).
Math Mammoth Grade 7 curriculum (pre-algebra)