Painting method:

First, draw a horizontal straight line; ?

Second, take a point on a straight line as the origin;

Third, draw an arrow on the right side of the straight line to indicate the positive direction of the number axis;

Four, according to the need, with the length of a segment as the unit length, clearly marked on a straight line.

Extended data:

A straight line is a collection of countless points, and there are countless real numbers including positive real numbers, zero real numbers and negative real numbers. Because of their * * * nature, they use countless points on a straight line to represent real numbers.

At this time, a straight line with origin, positive direction and unit length is used to represent real numbers. When the right side is defined as the positive direction, the number represented by the upper point on the right side of two numbers on this straight line is always greater than the number represented by the upper point on the left side, positive numbers are greater than zero, and zero is greater than negative numbers.