Skill: Represent integers on a number line

An integer number line uses $0$ as the reference point.

• Positive integers are placed equal distances to the right of $0$.
• Negative integers are placed equal distances to the left of $0$.
• Each step represents $1$ unit.
• Opposite integers are the same distance from $0$ but on opposite sides.

Example: Represent $-4$ and find its opposite.

1. Start at $0$.
2. Because $-4$ is negative, move left.
3. Count four equal steps: $-1$, $-2$, $-3$, $-4$.
4. Mark the point at $-4$.

$$\text{left} \quad -4 \quad -3 \quad -2 \quad -1 \quad 0 \quad 1 \quad 2 \quad 3 \quad 4 \quad \text{right}$$

The opposite of $-4$ is $4$ because $-4$ and $4$ are both four units from $0$, but they are on opposite sides. Thus, $-4$ is represented four units left of $0$, and its opposite, $4$, is four units right of $0$.