Addition of Signed Numbers

Start from the position of the first number.

(1)To add a positive number, move to the right on the number line.

(2)To add a negative number, move to the left on the number line.

In the picture below, red ball shows the first number in the box.
Click on the number line at the sum in the box.

Subtraction of Signed Numbers

To subtract a singed number, add the opposite of the number.

(1)To subtract a positive number, add a negative number.

Example (+7)−(+3)=(+7)+(−3) (−7)−(+3)=(−7)+(−3)

Whichever sign the first number has, move to the left on the number line.

(2)To subtract a negative number, add a positive number.

Example (+7)−(−3)=(+7)+(+3) (−7)−(−3)=(−7)+(+3)

Whichever sign the first number has, move to the right on the number line.

In the picture below, red ball shows the first number in the box.
Click on the number line at the difference in the box.