"Number Axis" PPT Courseware 2

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"Number Axis" PPT Courseware 2

Integers and fractions are collectively called rational numbers.

introduce

On an east-west road, there is a bus station. There are a willow tree and a poplar tree 3m and 7.5m east of the bus station respectively. There is a locust tree and a telephone pole 3m and 4.8m west of the bus station respectively. Try to draw a diagram to represent this situation.

How to use numbers to concisely express the relative positional relationship (direction, distance) between these trees, telephone poles and bus stations?

Number axis: A straight line that specifies the origin, unit length and positive direction is called a number axis.

(1) Choose any point on the straight line to represent the number 0. This point is called the origin;

(2) It is usually specified that the positive direction on a straight line is from the origin to the right (or up), and the negative direction is from the origin to the left (or down);

(3) Select an appropriate length as the unit length. On the straight line from the origin to the right, take a point every other unit length to represent 1, 2, 3,...; from the origin to the left, use a similar method to represent -1, - 2,-3,…

Drawing a number axis must reflect the three elements of the number axis: the origin, the positive direction, and the unit of length. All rational numbers can be represented by points on the number axis.

1. Observe the characteristics of the points on the number axis: the point representing the number 3 on the number axis is to the right of the origin, and the distance from the origin is 3 units; the point representing the number -2 is to the left of the origin, and the distance from the origin is 2 units. unit length.

Generally speaking, assuming a is a positive number, then the point representing the number a on the number axis is on the ______ side of the origin, and the distance from the origin is ______ unit length; the point representing the number -a is on the ______ side of the origin The side is ______ units long from the origin.

On a number line, the number represented by the point on the right is greater than the number represented by the point on the left.

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

3. Summary

(1) Number axis concept: A straight line that specifies the origin, unit length and positive direction is called a number axis.

(2) The three elements of the number axis: origin, positive direction, and length unit

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"Number Axis" PPT courseware 3:

"Number Axis" PPT courseware 3 Learning objectives: 1. Understand the meaning of the number axis, clarify the three elements of the number axis, and be able to draw the number axis correctly. 2. Be able to tell the number represented by a known point on the number line; be able to express rational numbers as points on the number line. Independent learning 1...

"Number Axis" PPT courseware:

"Number Axis" PPT courseware learning objectives: 1. Know the definition of a number axis, and be able to draw a number axis; 2. Be able to represent known numbers on a number axis, and be able to tell the numbers represented by points representing rational numbers on the number axis; 3 .Use the number axis to solve related problems and summarize the combination of numbers and shapes..

"Number Axis" Rational Numbers and Their Operations PPT Courseware 2:

"Number Axis" Rational Numbers and Their Operations PPT Courseware 2 1. As shown in the figure, a, b, c, the numbers represented are _______ numbers, _______ numbers, and _______ numbers respectively; 2. Which of the following statements is wrong ( ) A. The number line is a straight line B. The point representing -1 is 1 unit away from the origin C..

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Update Time: 2024-11-14

This template belongs to Mathematics courseware Qingdao Edition Seventh Grade Mathematics Volume 1 industry PPT template

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