Synchronous exercises of eighth grade mathematics

Synchronization exercise in absolute value class

Basic platform

1.； ; ; .

2.； ; .

3.； ; .

4. The reciprocal of _ _ _ _ is itself, the absolute value of _ _ _ is itself, and the absolute value of _ _ _ is its reciprocal.

5. The absolute value of a number is, then this number is _ _ _ _ _.

6. when,; When.

7. The number whose absolute value is equal to 4 is _ _ _ _.

8. The number whose absolute value is equal to its opposite number must be ........................................................... [

A. negative number B. positive number C. negative number or zero D. positive number or zero

Autonomous detection

1.； ; ; .

2. The absolute value of is _ _ _ _ _; Numbers whose absolute values are equal to _ _ _ _ _ _, they are _ _ _ _ _.

3. On the number axis, the absolute value is 4, and the rational number represented by the point to the left of the origin is _ _ _ _ _ _ _ _.

4. if, then,

5. The correct one of the following statements is .....................................................................................................................................................................

A. It must be a negative number B. Only when two numbers are equal can their absolute values be equal.

C. If the sum is opposite, D. If a number is less than its absolute value, it is negative.

6. Give the following statements: ① The absolute values of two mutually opposite numbers are equal; ② The number whose absolute value is equal to itself is only a positive number; ③ The absolute values of two unequal numbers are not equal; Two numbers with equal absolute values must be equal.

Among them, the correct one is ....................................................................................... []

A.0 B. 1 C.2 D.3

7. If is, the value range of is ....................................................... [

A. > outer diameter ≥ outer diameter ≤ outer diameter < o

8. Represent the following numbers on the number axis:

( 1) ; (2) ; (3) Negative numbers with an absolute value of 2.5; (4) The absolute value is positive 3.

9. According to the quality requirements, the net content (excluding packaging) of bottled edible blending oil produced by an enterprise can have an error of 0.002 L. Now six bottles of edible blending oil are randomly selected, and the number of liters exceeding the prescribed net content is recorded as positive, and the number of liters below the prescribed net content is recorded as negative. The inspection results are as follows:

+0.00 18

-0.0023

+0.0025

-0.00 15

+0.00 12

+0.00 10

Please use absolute knowledge to explain:

(1) Which bottles meet the requirements (that is, within the error range)?

(2) Which bottle's net content is closest to the specified net content?

Extended platform

1. Then; , then.

2. If, then,.