Very 1 1 answer the math seven times.

First, multiple-choice questions: (This big question * * 10 small questions, 3 points for each small question, * * 30 points. )

1. The following calculation is correct ()

A.x5+x5=x 10 B.x5？ X5 = x 10 c .(X5)5 = x 10d . x20÷x2 = x 10

2. The length of the following groups of three line segments can form a triangle is ()

A . 1cm，2cm，3cmB. 1cm， 1cm，2cm

C. 1cm，2cm，2cm； D. 1cm，3cm，5cm

3. As shown in the figure, when the master builds a door, he usually fixes the rectangular door frame ABCD with wooden strips EF.

Make it not deformed, and the basis for doing so is ().

A. The line segment between two points is the shortest B. All four corners of a rectangle are right angles.

C. Stability of rectangle D. Stability of triangle Figure 3

4. The approximate figure of 30,000 yuan obtained by rounding is ()

A. accurate to tens of thousands of digits, 1 significant digit. B. accurate to one digit, 1 significant digit.

C. accurate to 1%, with three significant figures. Accurate to 1%, with three significant figures.

5. The degree of an angle is 40, so the degree of its complementary angle is ().

a60 b . 140 c . 50d . 90

6. The probability of drawing red balls from a bag is that there are five red balls in the bag, so the number of * * * balls in the bag is ().

A. 1

7. As shown in the figure, naughty Xiao Cong puts the right vertex of the teacher's right triangle on the two parallel lines A and B of the blackboard in class, and it is known that ∠ 1 = 55, then ∠2 is ().

A.35 B . 45 C. 55 D. 125

8. If yes, type A should be ()

A.B. C. D。

9. Observe a string of numbers: 0, 2, 4, 6, ... The nth number should be ().

a . 2(n- 1)b . 2n- 1 c . 2(n+ 1)d . 2n+ 1

10. In △ABC and △DEF, ∠ A = ∠ D = 90, then it cannot be judged that △ABC and △DEF are congruent () under the following conditions.

A.AB=DE，AC=DF？ B. AC=EF，BC=DF C. AB=DE，BC=EF？ D.∠C=∠F，BC=EF

II. Fill in the blanks (6 small questions in this big question, 3 points for each small question, *** 18 points)

1 1. Please write a monomial with only letters m and n, so that its coefficient is-1 and the degree is 6. Then this monomial can be _ _ _ _ _ _ _.

12. Choose to do the problem (only choose to do one of the following two questions, and if you do two questions, you will only be graded according to the first question (1))

(1) expressed by scientific notation: 0.000000801= _ _ _ _ _ _.

(2) Rounding to the nearest round: 207,300 (two significant figures are reserved), and the obtained approximate number is _ _ _ _ _ _ _ _.

13. Calculate _ _ _ _ _ _ _.

14. Xiaoming wants to call the teacher, but he can't remember the last number. He dials one at random, and the probability of getting through is _ _ _ _ _ _ _ _ _.

15. As shown in the figure, it takes _ _ _ _ _ _ _ _ cards to make a square with a side length of A+B.

16. As shown in the figure, ∠ E = ∠ F = 90, ∠ B = ∠B=∠C, AE = AF, and the following conclusions are given: ① ∠1= ∠ 2; ②BE = CF； ③CD = DN； ④△CAN?△BAM, in which the correct conclusion is _ _ _ _ _ _ _ _ _ _ _. (Note: Fill in the serial numbers of all the conclusions you think are correct)

Three. (This big title is ***3 small questions, 17 small questions 6 points, 18 and 19 small questions 7 points, * * * 20 points).

17. Calculation problem:

18. As shown in the figure (1), it is known that: ∠AOB, point P is on OA, please take p as the vertex.

PA is one side ∠APC=∠O (Draw with a ruler, don't write, keep it.

Draw a line) prompt; Consider the problem comprehensively. [Source: Z_xx_k.Com]

(2) According to the chart above, answer:

Are PC and OB necessarily parallel?

19. Simplify first and then evaluate:, in which

Four. (This big question is *** 2 small questions, each with 8 points, *** 16 points)

20. As shown in the figure, to judge whether DF is parallel to CB, we can

Which angles to measure; Please write two plans and explain the reasons.

[Source: Science, Science, Internet]

2 1. Yucai Middle School Library counted the book borrowing volume in April, and the librarian drew a statistical chart (pictured).

(1) Is this statistical chart complete? What else do you need to add?

(2) If 2400 books are borrowed from the third grade, please find out the total number of books borrowed from the high school.

Verb (abbreviation of verb) (this big question is ***2 small questions, 8 points for every 22 small questions, 9 points for the 23rd small question, *** 17 points)

22. The trademark of a product is shown in the figure. O is the intersection of AC and BD, AO = DO, AB = CD. Xiaohua thinks of △ ABO △ DCO in the figure, and her problem solving process is:

At △ A wave and △DCO.

AO=DO

∠AOB=∠DOC

AB=CD

∴△abo?△dco

Do you think Xiaohua's problem solving process is correct? If it is correct, she uses

What are the conditions for judging the congruence of triangles? If it is not correct,

Please add a condition and write down your problem-solving process.

23. An opaque bag contains two white balls and 1 red balls, all of which are the same except the color.

(1) Pick a ball at random after stirring, and find the probability that it is not a white ball;

(2) After stirring, you can randomly pick a ball from it. If the probability of picking out the red ball is 0, how to add the red ball?

Vi. (This big topic ***2 small questions, 24 small questions 9 points, 25 small questions 10 points, *** 19 points)

24. as shown in the figure, in △ABC and △DEF, ∠ b = ∠ e = 90, BC = a, AC=b, EF= m, DF=n, a, b, m and n satisfy the following conditions:

(1) △ABC △ ABC and △DEF are congruent? Please provide a justification for the answer.

(2)AB‖DE？ Why?

25. As shown in the figure: E is on the line segment CD, EA and EB are divided into ∠DAB and ∠CBA respectively, and the point F moves on the line segment AB.

Ad = 4 ㎝，BC = 3 ㎝，AD‖BC。

(1) What do you think is the positional relationship between AE and BE? And verify your conclusion;

(2) When point F moves to a distance of ÷, can △ADE be congruent with △AFE? Why?

(3) In the case of (2), is BF = BC at this time? Why? Find the length of AB.

Reference answer to the seventh grade mathematics examination paper of Ji' an eight schools joint examination

First, multiple-choice questions: (This big question * * 10 small questions, 3 points for each small question, * * 30 points. )

1.b，2。 c，3。 d，4。 d，5。 c，

6.C7。 Answer, 8. b，9.A. 10。 B.

II. Fill in the blanks (6 small questions in this big question, 3 points for each small question, *** 18 points)

1 1. The answer is not unique, such as-,12. (Ⅰ) .8.0 1 х 10-7 (Ⅱ) .2. 1 х 105,65448.

15.2, 16.①②④

Three. (This big title is ***3 small questions, 17 small questions 6 points, 18 and 19 small questions 7 points, * * * 20 points).

17.

=[a2 B2-9-2 a2 B2+9]⊙(AB)-2 points.

=[-a2 B2]÷4 points.

=-A B-6 points.

18.( 1) Sketch (2 points in each case)-4 points.

(2) Answer: PC and OB are not necessarily parallel. -Seven points.

19. Solution: Original formula =

=-4 points.

Replace, acquire

Original formula =

= =-2- 1 =-3-7 points.

Four. (This big question is ***2 small questions, each with 8 points, *** 16 points)

20.( 1)∠ADF =∠B； The same angle is equal and two straight lines are parallel.

(2)∠BDF+∠B = 180； The internal angles on the same side are complementary and the two straight lines are parallel.

..... the answer is not unique. Write the plan correctly and give 4 points.

2 1. Solution: (1) This statistical chart is incomplete, and it is necessary to add the title and the number of books borrowed by each grade (or each pictogram indicates the number of books borrowed)-.

②6400 books-4 points.

Verb (abbreviation of verb) (this big question is ***2 small questions, 8 points for every 22 small questions, 9 points for the 23rd small question, *** 17 points)

22. Solution: Xiaoming's thinking process is incorrect ... 1 min.

The conditions to be added are: ∠B=∠C (or ∠A=∠D, or meet the requirements) …3 points.

At △ A wave and △DCO.

∠B=∠C

∠AOB=∠DOC

AB=CD

∴△ ABO△ dco (AAS)-8 points (the answer is not unique).

23. The probability that (1) is not a white ball is 4 points.

(2) Add the red ball for 3-9 points.

Vi. (This big topic ***2 small questions, 24 small questions 9 points, 25 small questions 10 points, *** 19 points)

24. Solution (1)-1.

Reason: