Numbers below zero are called negative numbers. Numbers above zero are called whole numbers. There are rules you can use if adding, subtracting, multiplying or dividing positive and negative numbers.

To add and subtract numbers always begin counting from zero.

When **adding** positive numbers, count to the **right**.

When **subtracting** positive numbers, count to the **left**.

Calculate .

Imagine moving up and down a number line to get to the answer.

Starting from zero, count up to . Then subtract . Then subtract . The answer is .

- Question
Calculate: .

The answer is or .

- When
**adding**positive numbers, count to the**right**. - When
**adding**negative numbers, count to the**left**. - When
**subtracting**positive numbers, count to the**left**. - When
**subtracting**negative numbers, count to the**right**.

Remember:

**subtract**when two different signs appear next to each other**add**when two of the same signs appear next to each other

(or )

- Question
Calculate:

a)

b)

a)

b)