Mixed operation of rational numbers in junior one mathematics

Fill in the blanks:

The multiplication rule of (1) rational number is: multiply two numbers, The number of the same symbol is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(2) If the product of four rational numbers A, B, C and D is positive, the number of negative numbers in A, B, C and D may be _ _ _ _ _ _ _ _ _ _;

(3) Calculate (-2/199) * (-7/6-3/2+8/3) = _ _ _ _ _ _ _ _ _;

(4) Calculation: (4a) * (-3b) * (5c) *1/6 = _ _ _ _ _ _ _ _ _ _ _;

(5) Error in calculation: (-8) * (1/2-1/4+2) =-4-2+16 =10 is _ _ _ _ _.

(6) Calculation: (-1/6) * (-6) * (17) * (-7/10) = [(-16) * (-6)].

First, multiple-choice questions:

1.|-5 | equals ........................................... ()

(A)-5 (B)5 (C) 5 (D)0.2

2. The number represented by the origin and the point to the right of the origin on the number axis is ....................... ().

(a) Positive number (b) Negative number (c) Non-positive number (d) Non-negative number

3. The algebraic expression "the difference between the products of two numbers B and M" is ..................... ().

(A) (B) (C) (D)

4. The number whose reciprocal equals itself is .................................... ().

(A) 1 (B)2 (C)3 (d) countless.

5. Of the six numbers (n is a positive integer), the number of negative numbers is ..................................................... ().

1 (B)2 (C)3 (D)4。

6. If point A and point B on the number axis correspond to rational numbers A and B respectively, the following relationship is correct ().

(A)a B；

B.a = B；

C.a < B；

D. not sure.

62. When m=- 1, -2m2-[-4m2+(-m2)] equals [].

A.-7;

B.3

c . 1；

D2。

63. When m=2 and n= 1, the polynomial -m-[-(2m-3n)]+[-(-3m)-4n] is equal to [].

a . 1；

B.9

C.3

D.5

[ ]

65.-5an-an-(-7an)+(-3an) equals []

A.- 16an；

B.- 16;

C.-2an；

D.-2.

66.(5a-3b)-3 (a2-2b) is equal to []

a . 3 a2+5a+3b；

b . 2 a2+3b；

c . 2 a3-B2；

D.-3a2+5a-5b。

67.X3-5x2-4x+9 equals []

A.(x3-5 x2)-(-4x+9)；

b . x3-5x 2-(4x+9)；

C.-(-x3+5 x2)-(4x-9)；

D.x3+9-(5x2-4x)。

[ ]

The result of 69.4x2y-5xy2 should be []

A.-x2y；

B.- 1;

C.-x2y 2；

D. None of the above answers are correct.

(3) simplification

70.(4x2-8x+5)-(x3+3x2-6x+2)。

72.(0.3x 3-x2y+xy2-y3)-(-0.5x 3-x2y+0.3 xy2)。

73.-{2a2b-[3abc-(4ab2-a2b)]}。

74.(5a2b+3a2b 2-ab2)-(-2ab 2+3a2b 2+a2b)。

75.(x2-2 y2-z2)-(-y2+3 x2-z2)+(5x 2-y2+2z 2)。

76.(3 a6-a4+2 a5-4 a3- 1)-(2-a+a3-a5-a4)。

77.(4a-2b-c)-5a-[8b-2c-(a+b)]。

78.(2m-3n)-(3m-2n)+(5n+m)。

79.(3 a2-4 ab-5 B2)-(2 B2-5a 2+2ab)-(-6ab)。

80.xy-(2xy-3z)+(3xy-4z)。

8 1.(-3x 3+2 x2-5x+ 1)-(5-6x-x2+x3)。

83.3x-(2x-4y-6x)+3(-2z+2y)。

84.(-x2+4+3x4-x3)-(x2+2x-x4-5)。

85. If A=5a2-2ab+3b2 and B=-2b2+3ab-a2, calculate a+b. 。

86. It is known that A=3a2-5a- 12, B=2a2+3a-4, and find 2 (a-b).

87.2m-{-3n+[-4m-(3m-n)]}。

88.5m2n+(-2m2n)+2mn2-(+m2n)。

89.4(x-y+z)-2(x+y-z)-3(-x-y-z)。

90.2(x2-2xy+y2-3)+(-x2+y2)-(x2+2xy+y2)。

92.2(a2-a b-B2)-3(4a-2b)+2(7 a2-4a b+B2)。

94.4x-2(x-3)-3[x-3(4-2x)+8]。

(4) Simplify the following categories before evaluating.

97. Given a+b=2 and a-b=- 1, find the value of 3(a+b)2(a-b)2-5(a+b)2×(a-b)2.

98. It is known that A=a2+2b2-3c2, B=-b2-2c2+3a2, C=c2+2a2-3b2, and find (A-B)+C. 。

99.Find (3x2y-2x2y)-(xy2-2x2y), where x=- 1 and y = 2.

10 1. Given |x+ 1|+(y-2)2=0, find the value of algebraic expression 5(2x-y)-3(x-4y).

106. when P=a2+2ab+b2 and Q=a2-2ab-b2, find p-[q-2p-(p-q)].

107. Find the value of 2x2-{-3x+5+[4x2-(3x2-x=-3. 1)], where x =-3.

1 10. When x=-2, y=- 1 and z=3, find the value of 5XYZ-{2x2y-[3xXYZ-(4xy2-x2y)]}.

1 13. Given A=x3-5x2 and B=x2-6x+3, find a-3 (-2b).

(5) Comprehensive exercises

1 15. Remove the brackets: {-[-(a+b)]}-{-[-(a-b)]}.

1 16. Delete the brackets: -[-(-x)-y]-[+(-y)-(+x)].

1 17. Given A=x3+6x-9 and B=-x3-2x2+4x-6, calculate 2A-3B, and put the result in brackets with "-"in front.

1 18. Calculate the following formula and put the result in brackets with "-"in front:

(-7 y2)+(-4y)-(-y2)-(+5y)+(-8 y2)+(+3y)。

1 19. Remove the brackets, merge similar items, and arrange the results according to the ascending power of x, and put the last three items in brackets with "-":

120. Without changing the value of the following formula, change the symbol before each bracket to the opposite symbol: (x3+3x2)-(3x2y-7xy)+(2y3-3y2).

12 1. Put the cubic term of polynomial 4x2y-2xy2+4xy+6-x2y2+x3-y2 in brackets with "-"in front, the quadratic term in brackets with "+"in front, and the quartic term and constant term in brackets with "-"in front.

122. Remove the brackets of the following polynomials, combine similar terms, put them in brackets with "-"in front, and then find the value of 2x-2[3x-(5x2-2x+ 1)]-4x2, where x =- 1.

123. Merge similar projects:

7x- 1.3z-4.7-3.2x-y+2. 1z+5-0. 1y。

124. Merge similar items: 5m2n+5mn2-Mn+3m2n-6mn2-8mn.

126. Remove brackets and merge similar items:

( 1)(m+ 1)-(-n+m)；

(2)4m-[5m-(2m- 1)]。

127. Simplified: 2x2-{-3x-[4x2-(3x2-x)+(x-x2)]}.

128. Simplification:-(7x-y-2z)-{[4x-(x-y-z)-3x+z]-x}.

129. Calculation: (+3a)+(-5a)+(-7a)+(-31a)-(+4a)-(-8a).

130. Simplification: a3-(a2-a)+(a2-a+1)-(1-a4+a3).

13 1. Combine the similar items of x2-8x+2x3- 13x2-2x-2x3+3 and evaluate them, where x =-4.

132. Fill in the appropriate items in brackets: [()-9y+()]+2y2+3y-4 =11y2-()+13.