Time to clear up the confusion on these two once and for all! Not sure why cross canceling (cancelling if you're European) had to get that name, since it really causes a lot of confusion with cross multiplication, and since if you do one when you should do the other, you'll get the question totally wrong. But hey, every book and teacher calls these things by these same confusing names, so hopefully this video will help!
Intro to Variables & Expressions (free)
Let’s face it, the craziest thing about algebra is it’s the first time you see letters in math. X is the most famous of them, but we can use any other letter of the alphabet (and I often will to get you used to it). In this video, we’ll quickly talk about what variables and expressions are, then we’ll get some practice using them, and plugging numbers in for x to "evaluate" expressions.
If you do not have an account, you should get one, because it is awesome! You can save a playlist for each test or each chapter, and save your "greatest hits" into a "watch right before the final" list (not that we recommend cramming, but when in Rome...)