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+3d .-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. The difference between two negative numbers must be greater than zero. C. the subtraction of positive numbers is actually the algebraic sum of two positive numbers. D. A positive minus a negative equals the absolute value of a negative plus a positive.
(6) Equation -3-5 cannot be read as ()
A. The difference between-3-3 and -5 The sum of B- 3-3 and -5 The difference between c-3-3 and -5 is d-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。
Complete sets of math calculation problems and optimization training of answer quality in junior one.
( 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 whether the equation: a-(b-c+d)=a-b+c-d is true.
( 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
Reference answer:
Synchronous outline exercise
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.
Quality optimization training 1. ( 1)-,+,+; (2)-,+,-,-; (3)+,+; (4)-,+,+; (5)-,+,-.2. (1) (2) (3) (4)-3. (1) (2) All hold .4. ( 1)-(2) (3)-29.