This course introduces the integers. They are the counting numbers, zero, and the numbers below zero. It is for a student meeting negative numbers for the first time. Most of it is built on the number line, so each rule is shown rather than simply given.
You begin with what integers are, and where each one sits on the line. You learn why is smaller than . A thermometer and the floors below a building are used as examples. Addition comes next, as a walk along the line. A plus sign walks you right and a minus sign walks you left.
Subtraction follows, including why taking away a negative is the same as adding. Multiplication is then shown as adding a number again and again. A pattern explains why two negative numbers give a positive answer. Division comes last, and uses the same sign rule as multiplication.
By the end you will be able to:
- put integers in order, and say which of two negative numbers is smaller.
- add integers, including longer sums such as .
- subtract one integer from another, and get subtract from the right way round.
- multiply two integers, and work out the sign of the answer.
- divide integers, and say why you can never divide by .