Negative Numbers and Rounding

Negative numbers and rounding are two important topics that come up regularly on the CSSE maths paper. Negative numbers appear in temperature problems and number-line questions, while rounding is used in estimation and checking answers. Let us look at both in detail.

---

Negative Numbers

Negative numbers are numbers less than zero. They are written with a minus sign in front, such as -3, -7, or -15.

The number line

On a number line, negative numbers sit to the left of zero.

... -5 -4 -3 -2 -1 0 1 2 3 4 5 ...

Key facts

• -3 is less than -1 (it is further from zero on the left).
• The further left a number sits, the smaller it is.
• Zero is neither positive nor negative.
• -10 is smaller than -2, because -10 is further from zero.

---

Ordering Negative Numbers

Worked Example

Put these numbers in order from smallest to largest: 3, -5, 0, -1, 7, -3

On the number line: -5, -3, -1, 0, 3, 7

Answer: -5, -3, -1, 0, 3, 7

---

Adding and Subtracting with Negative Numbers