Читать книгу SAT Math For Dummies with Online Practice - Mark Zegarelli - Страница 60

Arithmetic is the mathematics of numbers and operations upon them — essentially, number crunching. I cover a lot of this material in Basic Math & Pre-Algebra For Dummies (Wiley). When you know how to perform the operations in a given problem in the correct order (using the order of operations, affectionately remembered as PEMDAS), you’re well on your way to a complete mastery of arithmetic. In fact, you may already be a winner.

In contrast, algebra takes arithmetic one step further by introducing the variable, which is often named x. Algebra is the place that some of the nicest people you will ever meet — possibly, your parents — threw in the towel on math. And then, when they meet me at a party (yes, math teachers sometimes go to parties), they say, “OMG, I could never learn algebra!”

I feel their pain. At the same time, even though using variables can be tricky, there is no law that says arithmetic is always easier than algebra. For example:

Arithmetic Problem	Algebra Problem

You can probably see that in the algebra problem shown here, the value of x is 4. In contrast, the answer to the arithmetic problem is left for the reader to solve (which is a fancy way teachers get to pose hard questions without having to answer them!).

The take-away here is that arithmetic is math that involves numbers and operations on them, and algebra includes variables.