In basic mathematics, a number line is a picture of a horizontal straight line on which every point is assumed to correspond to a real number and every real number to a point.
It is divided into two symmetric halves by the origin, i.e. the number zero.
Customarily, positive numbers lie on the right side of zero, and negative numbers lie on the left side of zero. An arrowhead on either end of the drawing is meant to suggest that the line continues indefinitely in the positive and negative real numbers.

Type the missing number.

Each interval represents 1, so find the missing number by adding or subtracting 1.
The missing number is larger than -4, so add 1.
Since -4 + 1 = -3, the missing number is -3.