Negative numbers & integers on a number line
Theory
Integers are the whole numbers, zero and the negative whole numbers: \(\ldots, -3, -2, -1, 0, 1, 2, 3, \ldots\). Negative numbers sit to the left of zero on a number line. This Year 6 maths page shows how to place, compare and order integers, and how to count up and down past zero in real situations.
An integer is a whole number that can be positive, negative or zero. \(-4\), \(0\) and \(7\) are integers; \(-2.5\) and \(\dfrac{1}{2}\) are not.
Negative numbers are less than zero and are written with a minus sign. They describe temperatures below zero, depths below sea level and floors below ground.
On a number line, numbers get larger to the right and smaller to the left. So \(-2 > -5\): \(-2\) is to the right of \(-5\).
For negative numbers, the further from zero, the smaller the number: \(-9\) is colder than \(-4\).
Ascending order is smallest to largest; descending is largest to smallest.
Comparing and moving along the number line:
Ordering integers
- Picture the number line.
- Start with the negative number furthest from zero (the smallest).
- Work right: negatives closest to zero, then \(0\), then positives.
Moving past zero
- Count from the start to zero.
- Count on the remaining steps on the other side.
| \(-5 + 3\) | \(=\) | \(-2\) |
A is \(-5\); \(3\) steps right is \(-2\).
\(-8\), because it is further left on the number line.
\(-8, -6, -1, 0, 4\).
| \(6 - 10\) | \(=\) | \(-4\) |
\(-4^\circ\)C, as on the thermometer.
(i) Write this as an integer.
(ii) She rises \(3\) m. Where is she now?
| \(-8 + 3\) | \(=\) | \(-5\) |
(i) \(-8\)
(ii) \(-5\), still \(5\) m below sea level
| \(1 - 4\) | \(=\) | \(-3\) |
Level \(-3\) (three levels below ground).
The integers between are \(-3\) and \(-2\); the odd one is \(-3\).
For negatives, further from zero means smaller. \(-9 < -4\), so \(-4\) is greater.
Common pitfalls
Frequently asked questions
What is an integer?
A positive or negative whole number, or zero.
Where do negative numbers go on a number line?
To the left of zero.
Which is bigger, β2 or β5?
\(-2\), because it is closer to zero (further right).
What is 2 β 7?
\(-5\): count \(2\) back to zero, then \(5\) more.
Where are negative numbers used?
Temperatures below zero, places below sea level, floors below ground and money owed.