Head First Algebra

Appendix B. Pre-Algebra Review: Build on a solid foundation

Do you ever feel like you can’t even get started? Algebra is great, but if you want to learn it, you have to have a good understanding of number rules. Suppose you’re rolling along and realize that you forgot how to multiply integers, add fractions, or divide a decimal? Well, you’ve come to the right place! Here we’re going to cover all the pre-Algebra you need—fast.

Algebra starts with numbers

If you hear the weatherman say it’s “minus five,” you know that it’s really cold, colder than zero. Numbers sometimes need to indicate that they are less than 0, and they do that by adding a negative (or minus sign) in front of the number.

So, that’s a negative number. What are the other numbers, the plain ones? Those are positive numbers. They are indicated by no sign or a positive sign. If you’re working with whole positive and negative numbers, it means that you’re working with integers.

Sum it up

Integers - The whole numbers, including all of the negative numbers, zero, and positive numbers.

{...,–3, –2, –1, 0, 1, 2, 3...}

How do you work with negative numbers?

Operations with negative numbers are similar to operations with positive numbers; ...