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The seventh grade second volume math competition
Wenzhou Tongde Middle School Grade Seven Mathematics Competition Examination Questions

Proposer: Chen Zheng.

title

One, two, three, total score

19 20 2 1 22

get

minute

Tip:

1. Examination time 100 minutes, full mark 100 minutes;

2. Please fill in the class, name and admission ticket number in the sealed area of the answer sheet before answering the question.

First, multiple-choice questions (4 points for each small question, 40 points for * * *)

1, rational number A equals its reciprocal, so a2006 is ().

A, the largest negative number b, the smallest non-negative number c, the smallest absolute integer d and the smallest positive integer

2. The value of (-0.125) 2005× (-8) 2006 is ().

a、4 B、4 C、8 D、8

3. If is, the value of cannot be ().

a、0 B、 1 C、2 D 、-2

4. When the value of the contemporary algebraic expression x2+3x+5 is equal to 7, the value of the algebraic expression 3x2+9x-2 is equal to ().

a、4 B、0 C、-2 D、-4

5. The distance between the snail and the wellhead 1 m in the well. It climbs 30 centimeters every day, but slides down 20 centimeters. Every night. The number of days for snails to climb out of the wellhead is ().

A, 8 days b, 9 days c, 10 days d, 1 1 day

6. The area of black tea fungus in the jar doubles every day. If the whole tank surface is filled in 19 days, half tank surface will be filled in () days.

a、5 B、7 C、 16 D、 18

7. As shown in the figure, fold the figure on the left and it becomes ().

8. As shown in the figure, it is an expanded diagram of a cube, and the numbers on the reverse side are the same, so the numbers on the A, B and C surfaces are () respectively.

a、2、5、3 B、3、5、2 C、3、2、5 D、5、2、3

9. If △ +△ =★, ○ =□ +□, △ = ○+○, then ★ ○□ = ()

a、2 B、4 C、8 D、 16

10, let "●, ▲, ■" respectively represent three different objects, as shown in the following figure. The first two kinds of balance are balanced. If you want to balance the third balance, then "?" The number of "■" should be ()

a、5 B、4 C、3 D、2

Fill in the blanks (4 points for each small question, 32 points for * * *)

1 1, the inverse of-is _ _ _ _ _;

12. On the number axis, the number whose distance from the point representing 2 is equal to 3 is _ _ _ _ _ _ _ _;

13, assuming that the prescription of m is-,then the valve AE is _ _ _ _ _ _ _. (English-Chinese dictionary: hypothesis; Countdown; Value value. )

14. Replace one of the non-zero numbers with the number 3 in -0. 1428, and make the obtained number maximum, and the replaced number is _ _ _ _ _ _ _ _ _ _ _;

15. Stack 14 cubes with a side length of 1 on the ground to form a solid as shown in the figure, and then paint the exposed surface part in red, so the area of the red part is _ _ _ _ _ _ _ _ _;

16, at the Spring Festival party, the electrician hung a circle of lanterns around the auditorium, and the arrangement rules were: green, yellow, red, green, yellow, red, green, yellow, red, red, red, red, red, red, red, red, red.

17, the length of the rectangle is acm and the width is 5cm. After the length is reduced by 2cm and the width is increased by 2cm, the rectangular area is larger than the original rectangular area.

18、 _____________.

Iii. Answer questions (6 points for 19, 6 points for 20 questions and 8 points for 2 1 question). 22 questions and 8 points)

19, simplification evaluation: 2-2 (2-3xy)+3 (y2-2y)-2y2, where =, y =-1;

20. Explore the law: observe the following figures and fill in the table below:

The number of straight lines is 1 234 56...n

The maximum intersection number is 0 1 36. ...

2 1, Euler, a mathematical giant in history, first expressed the polynomial about x with the symbol f(x). For example, f(x)=x2+3x-5. When x= a certain number, the value of the polynomial is expressed by f (a certain number). For example, when x=- 1, the value of polynomial x2+3x-5 is recorded as

f(- 1)=(- 1)2+3×(- 1)-5 = 7;

(1) It is known that g(x)=-2x2-3x+ 1, and the values of g(- 1) and g(-2) are obtained respectively.

(2) Given that h(x)=ax3+2x2-x- 14, h( 12 )=a, find the value of A. ..

22. Please answer the following questions according to the information provided in the picture:

84 yuan

38 yuan

(1) How much is a thermos and a glass?

(2) Two shopping malls, A and B, sell the same thermos bottles and cups at the same time. In order to welcome the new year, both shopping malls are engaged in promotional activities. A shopping mall stipulates a 10% discount on these two products; Shopping mall B stipulates that you can buy thermos bottles and send water cups for free. If a company wants to buy four thermos bottles and 15 cups, which shopping mall is more cost-effective, and explain the reasons.