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Number axis: a straight line that defines the origin, positive direction and unit length.

Characteristic analysis of number axis;

1. On the number axis, the number corresponding to the right point is always greater than the number corresponding to the left point.

2. Positive numbers are greater than 0, negative numbers are less than 0, and positive numbers are greater than all negative numbers.

Example 3( 1) Draw a number axis, and represent the following numbers on the number axis, and use "

Example 3(2) On the number axis, a point starts from the origin, first moves 2 unit lengths to the right, then moves 3 unit lengths to the left, and finally reaches the end point. At this time, the number represented by this point is

a、5 B、 1 C 、- 1 D 、-5

Example 3(3) The numbers represented by A and B on the number axis are -3 and 1 respectively, and point C is the midpoint of AB, so the number represented by point C is _ _ _ _ _ _.

Example 3(4) As shown in the figure, a part of the number axis is polluted by ink, and the polluted part contains integers.

Example 4: The number corresponding to point A on the (1) number axis is -3, so the number corresponding to point B with a distance of A 1 unit length is _ _ _ _ _ _ _.

Example 4(2) The number corresponding to point A on the number axis is-1. An ant crawls from point A to point B along several axes at the speed of 3 unit lengths per second, eats the honey at point B in 2 seconds, and then returns to point A along the original road. * * * takes 6 seconds, so how many unit lengths does the ant crawl? How many unit lengths is the distance between point B and point A? What is the number corresponding to point B?