"New Curriculum Classroom Synchronous Exercise Book Mathematics (East China Edition Grade 8)"

Refer to the root of the number in chapter 12 of the answer.

1

12. 1 square root and cube root (1) i.1.b2.a3.b.

Second, 1. 49? 8? 4, 7 2.2, 2? 8? 4 3.- 1; 4.0

Three. 1. From left to right: 3, 4, 5, 6, 7, 8, 9, 10,1,12,65438.

15.

2.( 1) 25 (2) 0.0 1 (3)45

8? 4 (4)29

8? four

(5) 100 (6) 2

3.( 1) 0.2 (2) 3 (3)79

8? four

(4) 17

8? four

4.( 1) A >-2 (2) A =-2 (3) A

8? four

, 14

2. 10

8? four

, 1 03. (1) 25.53 (2) 4.114.0 or1.

Three. 1.( 1) 80 (2) 1.5 (3) 1 14

(4)3; 2.( 1)-9 (2) 12

8? four

(3)4 (4)-5

3. (1) 2.83 (2) 28.09 (3)-5.34 (4) 0.47.4. The original side length of the square iron sheet is 5cm. 12. 1+0 square root and cube root (3) 1. 1.

27

8? 2,-3 2.6,-343 3.-4 4.0, 1,- 1.

Three. 1.( 1)0.4 (2)-8 (3)

Fifty-six

( 4) 1 1

2

8? 2 (5)-2 (6) 100;

2.( 1) 19.09(2)2.652(3)-2.098(4)-0.90 16; 3.63.0 square centimeters

;

4. Calculate: 0.5 15 1, 5.1,5 1, 5 15. 1, and get the rule: when the decimal point of the root sign is left (.

For every 2 digits, the decimal point of the square root is moved to the left (right) by 1 digit, and 0.002653 is obtained.

≈

0.05 15 1, 26530000≈5 15 1.

12.2 real number (1) 1, 1. B 2。 C 2, 1.3 omitted.

8? 2

3.x≥ 12

8? 2

.

Three. 1.( 1) √ (2) × (3) √ (4) × (5) × (6 )× (7) √ (8) ×; 2. The numbers in the rational number set are:

13

,3. 14 15,2, 16,-5,0,? 8? 2

8? 243.6,0.8

The numbers in the irrational number set are: 7, 34,? 8? 9,0. 10 100 1000 1…; 3. The number corresponding to point A is -3, the number of point B is-1.5, the number of point C is 2, the number of point D is 5, and the number of point E is? 8? 9.

12.2 real number (2) 1,1.c2.b3.b.

Second, 1. 2? 8? 2,2 2.( 1)3 1? 8? 2(2)23? 8? 2

3.5 .