(2)8+(-6.45)-42+9 1

(3)(-20)+(+3)-(-5)-7

(4)(-8)+ 10+2-57

(5)5.9+8.4-(-78)+(-3.8)

(6)4.8-(-69)+6.5-(-77)

(7)(-8)-6 1-(3 1)+(-2.9)

(8)9.3+(-7.2)-(+3)+5.2

(9)(-5)+ 13-(-5.8)-(-54)

( 10)(+ 13)-9.6+(-20)

[-|98|+76+(-87)]*23[56+(-75)-(7)]-(8+4+3)

5+2 1*8/2-6-59

68/2 1-8- 1 1*8+6 1

-2/9-7/9-56

4.6-(-3/4+ 1.6-4-3/4)

1/2+3+5/6-7/ 12

[2/3-4- 1/4*(-0.4)]/ 1/3+2

22+(-4)+(-2)+4*3

-2*8-8* 1/2+8/ 1/8

(2/3+ 1/2)/(- 1/ 12)*(- 12)

(-28)/(-6+4)+(- 1)

2/(-2)+0/7-(-8)*(-2)

( 1/4-5/6+ 1/3+2/3)/ 1/2

18-6/(-3)*(-2)

(5+3/8*8/30/(-2)-3

(-84)/2*(-3)/(-6)

1/2*(-4/ 15)/2/3

-3x+2y-5x-7y

Mixed operation of rational number addition and subtraction

1. Multiple choice question:

(1) Write -2-(+3)-(-5)+(-4)+(+3) in the form of omitting brackets, and the correct one is ().

A.-2-3-5-4+3 B.-2+3+5-4+3

C.-2-3+5-4+3 D.-2-3-5+4+3

(2) The result of calculating (-5)-(+3)+(-9)-(-7)+ is correct ().

A.- 10 B.-9 C.8 D.-23

(3) The algebraic sum of-7,-12 and +2 is less than the sum of their absolute values ()

A.-38 B- 4 c . 4d . 38

(4) If +(b+3)2=0, the value of b-a- is ().

A.-4 B.-2 C.- 1 D. 1

(5) The following statement is true ()

A. the subtraction of two negative numbers is equal to the subtraction of absolute values.

B the difference between two negative numbers must be greater than zero.

C. A positive number minus a negative number is actually the algebraic sum of two positive numbers.

D. negative negative positive equals the absolute value of negative plus positive.

(6) Equation -3-5 cannot be read as ()

The difference between A.-3 and 5. The sum of b. 3 and -5.

Difference between c-3 and -5d-3 minus 5

2. Fill in the blanks: (4 ′× 4 =16 ′)

( 1)-4+7-9=- - + ;

(2)6- 1 1+4+2=- + - + ;

(3)(-5)+(+8)-(+2)-(-3)= + - + ;

(4)5-(-3 )-(+7)-2 =5+ - - + - .

3. Write the following form in the form of sum, without brackets, and say two pronunciation ways: (8 ′× 2 =16 ′)

( 1)(-2 1)+(+ 16)-(- 13)-(+7)+(-6);

(2)-2 -(- )+(-0.5)+(+2)-(+ )-2.

4. Calculation problem (6 ′× 4 = 24 ′)

( 1)- 1+2-3+4-5+6-7;

(2)-50-28+(-24)-(-22);

(3)- 19.8-(-20.3)-(+20.2)- 10.8;

(4)0.25- +(- 1 )-(+3 ).

5. When x =-3.7, y =- 1.8 and z =- 1.5, find the value of the following algebraic expression (5 ′× 4 = 20 ′).

( 1)x+y-z； (2)-x-y+z； (3)-x+y+z； (4)x-y-z。

( 1) (-7)-(+5)+(+3)-(-9)=-7 5 3 9;

(2)-(+2 )-(- 1 )-(+3 )+(- )

=( 2 )+( 1 )+( 3 )+( );

(3)- 14 5 (-3)=- 12;

(4)- 12 (-7) (-5) (-6)=- 16;

(5)b-a-(+c)+(-d)= a b c d；

2. When x=, y=- and z=- respectively, find the values of the following algebraic expressions;

( 1)x-(-y)+(-z)； (2)x+(-y)-(+z)；

(3)-(x)-y+z； (4)-x-(-y)+z。

3. Verify the equations of the following three groups of numbers:

Is it true that a-(b-c+d)=a-b+c-d?

( 1)a=-2，b=- 1，c=3，d = 5；

(2)a=23，b=-8，c=- 1，d= 1。

Computational problem

( 1)- 1-23.33-(+76.76);

(2) 1-2*2*2*2;

(3)(-6-24.3)-(- 12+9. 1)+(0-2. 1);

(4)- 1+8-7

A water conservancy survey team swam 5 kilometers on the first day, 5 kilometers on the second day, 4 kilometers on the third day and 4.5 kilometers on the fourth day. Where is the survey team at this time? How many kilometers apart?

Reference answer:

1.( 1)C； (2)B； (3)D； (4) a; (5)C； (6)C 2。 ( 1)4,(-7),(-9) (2)(-6),(- 1 1),(-4),2; (3)-5,8,2,3; (4)3,7,2;

3. Omit 4. ( 1)-4; (2)-80; (3)-30.5 (4)-5

5.( 1)-4; (2)4; (3)0.4; (4)-0.4.

1.( 1)-,+,+; (2)-,+,-,-; (3)+,+; (4)-,+,+; (5)-,+,-,-.

2.( 1) (2) (3) (4)-

3.( 1) and (2) both hold.

4.( 1)-

(2)

(3)-29.5

(4)- 1 Question (4) Note that the numbers with the same sign and the opposite sign should be combined separately.

1. Upstream 1 km

Respondent: juli Andy- Chief Operating Officer level1210-413: 34.

Add:

5+(-2)

(-7)+9

(-4)+7+(- 15)

9+7+(-3)

2+(-5)

18+(-9)

29+(- 17)

(-28)+ 18

9+8+(-25)

(-26)+ 17

19+(-3)

(-32)+25

25+(-2 1)

5+ 19+(-36)

(-80)+60

128+(-72)+ 12

19+(- 17)

(-9)+7+(-23)

25+(- 19)

290+(-78)

(After 20 passes)

I hope you do well in the exam.

Practice more.