I. DDBBB DCDAB AC

Second, 13, (,(-), 9,), 8, (,(-), 2,), 6;

14、30.25286895; 15、230; 16、65、-35; 17,3; 18，20mm、20.05mm

19, 100、0; 20,2000 or 200 1

3.2 1, (1) omitted, (2) The minimum body temperature at 22 o'clock is 36.6℃, which is 2.5℃ lower than the maximum body temperature;

22、 , ,32

23. Profitable 5 yuan,

24、( 1)2 1℃

25.( 1) Lili needs to spend 8 yuan to get to and from work every week, and 9 yuan is needed for weekly tickets, so she should buy a one-way ticket.

(2) If Lili needs to use 2 yuan to go to the park on weekends, then the admission fee for this week is 10 yuan, so she should buy a weekly ticket.

(2) Answer:

I. 1. C 2。 A 3。 C 4 explosive D 5。 C 6。 D

Second,

7 . x =-68 . a = 9 . k =-4 10 . x =- 1

1 1. solution: 5-x is obtained by the difference between 5 and x, and is expressed as (5-x). If the difference between 5 and x is twice that of x, then 1 is (5-x)=2x+ 1 or (5-x)-2x =.

12. 1 13.。

14. Solution: If the absolute value of a number is 3, then this number is 3, so you get or =-3. Solve these two equations to get the value of x, and then you can get the answer to this question.

Slight solution: according to the meaning of the question, remove the denominator, brackets and shift items, and merge similar items so that x=-5 or x=7, and the coefficient is 1.

15 . x+(x-2)+(x-4)= 18 16. 1 1+2x = 3 1-2x，x=5

Third,

17. solution: remove the brackets and get 70% x+16.5-55% x =19.5.

If the item is shifted, 70% x-55% x =19.5-16.5.

Merge similar items, x= 12.

18. Solution: If the denominator is removed, 3x-(5x+11) = 6+2 (2x-4).

Without brackets, you get 3x-5x- 1 1=6+4x-8.

When the item moves, 3x-5x-4x=6-8+ 1 1.

Combine similar items and you get -6x=9.

The coefficient is 1 and x=.

19. Solution: Remove the brackets,

Move items, get

Merge similar projects to obtain

The coefficient is 1 and x=.

20. Solution: Multiply both numerator and denominator by 5 to get 5x-20.

Multiply the numerator and denominator by 20 to get 20x-60.

That is, the original equation can be simplified as 5x-20-2.5=20x-60.

5x-20 of the shifted item =-60+20+2.5,

Merging similar items gives-15x=-37.5,

The coefficient is 1 and x=2.5.

Fourth,

2 1. Solution ideas:

(1) Given m=4, we can get a linear equation about y by substituting +m=my-m, and then solve the equation about y. 。

(2) Substitute y=4 into +m=my-m to get a linear equation about m, and then solve this equation.

Solution: (1) Substitute m=4 into +m=my-m to get +4=4y-4. Move the term to get -4y=-4-4.

If similar items are combined, the result is =-8, the coefficient is 1, and y=.

(2) Substitute y=4 into +m=my-m to get +m=4m-m, and transpose the term to get 4m-m-m=2.

Combining similar terms, the result is 2m=2, the coefficient is 1, and the result is m= 1.

22. Solution 1: Let Wang Qiang run x meters at a speed of 6m/s, and then run (3000-x) meters at a speed of 4m/s. 。

According to the equation:

If you divide by the denominator, you get 2x+3 (3000-x) =10× 60×12.

Without brackets, 2x+9000-3x=7200.

Moving items, 2x-3x=7200-9000.

Combining similar terms, we get -x=- 1800.

The conversion coefficient is 1, and x= 1800.

Scheme 2: Let Wang Qiang run at a speed of 6m/s for x seconds, and Wang Qiang run at a speed of 4m/s for (10×60-x) seconds.

According to the equation 6x+4 (10x60-x) = 3000,

Without brackets, the result is 6x+2400-4x=3000.

For shifted items, 6x-4x=3000-2400.

Merge similar projects, 2x=600.

The conversion factors are 1, x=300, 6x=6×300= 1800.

A: Wang Qiang ran 6 meters per second 1800 meters.

23 .738

24. If the cost is reduced by X yuan, then

[5 10×( 1-4%)-(400-x)]×( 1+ 10%)m =(5 10-400)m，x = 65438+。

25. Solution: Let Xiao Zhao attend the summer camp. The number of dates in the middle of these seven days is X,

Then the dates of the remaining six days are (x-3), (x-2), (x- 1), (x+ 1), (x+2) and (x+3) respectively.

According to the equation: (x-3)+(x-2)+(x-1)+x+(x+1)+(x+2)+(x+3) = 84.

Without brackets, x-3+x-2+x-1+x+1+x+2+x+3 = 84.

Transfer project merger, 7x=84.

The chemical coefficient is 1 and x= 12, then x-3= 12-2=9.

So Xiao Wang went out on the 9th.

Let Xiao Wang go to his uncle's house for x,

Then the remaining six days are (x-3), (x-2), (x- 1), (x+ 1), (x+2) and (x+3) respectively.

According to the equation: (x-3)+(x-2)+(x-1)+x+(x+1)+(x+2)+(x+3) = 77.

If the solution is 7x = 77 and x = 1 1, then x+3= 14.

So Xiao Wang went home in July 14.

(3) Answer:

One,

1.97 27' 55 ÷ 2.6 3.30 4.13cm or 3cm 5. ∠AOE∠ Department of Energy ∠AOD and ∠ Bank of China.

6.( 1)B (2)A (3)B (4)C

7. Confusion in problem solving: From ∠BAC = 90, we can get the complementary angles of ∠ B and ∠C, and the complementary angles of the same angle are equal. Here, we must find the complementary angle of ∠ B in the graph to find the angle equal to ∠ C. Similarly, if we find the complementary angle of ∠ C.

Solution: As shown in the answer sheet.

∠∠BAC = 90 ,∴∠b+∠c=90。

∠ ADC = 90，∴∠ DAC+∠ C = 90。

∴∠B=∠DAC.

You can get ∠C=∠DAB in the same way.

8. The direction of 65 north-northwest or 25 north-northwest; Southeast 15 or southeast 75.

9.610.3011.519' 561'.12. Or ∠ 1-90.

13.1008014. (1) cuboid (2) prism (3) prism 15. (1) Front view (2) Top view (3) Left view 65448. Curved surface; plane

2.17.b18.a19.c.

20. Confusion in problem solving: First, carefully observe the graphics, give full play to the spatial imagination, and analyze and think about which of these four graphics can be restored to the original geometric graphics and which can't.

2 1.C

Three. 22.× 23.∨ 24.∨ 25.∨ 26.× 27.× 28.× 29.× 30.∨ 3 1.

Fourth,

32.( 1)∵C is the midpoint of AB.

∴AC=BC=？ AB=9 (cm).

D is the midpoint of AC,

∴AD=DC= AC=？ (cm).

E is the midpoint of BC,

∴CE=BE=？ BC=？ (cm)

And ∵DE=DC+CE,

∴DE=？ +=9 (cm).

(2) From (1), we know that AD=DC=CE=BE,

∴CE=？ BD。

CE = 5cm，

∴BD= 15(cm)

33. Solution: As shown in the answer sheet, ∫∠COE = 90, ∠ COF = 34.

∴∠EOF=90 -34 =56。

∫ equal share ∠AOE,

∴∠AOE=∠EOF=56。

∴∠AOC=∠AOF-∠COF=56 -34 =22。

∠∠AOC =∠BOD (equal to the vertex angle),

∴∠BOD=22。

34. Solution: Let this angle be α, then the complementary angle of this angle is 90-α and the complementary angle is 180-α.

According to the meaning, the solution is α = 75.

A: This angle is 75 degrees.

35. Solution: Let this angle be α, then the complementary angle is 90-α.

α= 180 - 123 24′ 16〃=56 35′44〃,

∴90 -α=90 -56 35′44〃=33 24′ 16〃.

A: The complementary angle of this angle is 33 24'16 ".

Five,

36. Puzzlement in problem solving: To make an angle equal to 3 ∠1-2, you must first make ∠AOD=3∠ 1 with O as the vertex and OA as the edge, and then make ∠AOD within ∠AOD.

Solution:

(1) Draw an arc with the vertex O of ∠ 1 as the center and the appropriate length as the radius, so that the rays OA and OB intersect at the points E and F respectively.

(2) intercept the upper arc in turn, and make.

(3) If light OD passes through point H from point O, ∠AOD is 3∠ 1.

(4) Draw two sides of the arc intersecting with ∠2 at m ′ and n ′ with the vertex of ∠2 as the center and the appropriate length as the radius.

(5) Draw an arc intersection point OA at point M with O as the center and equal length as the radius.

(6) Draw a pre-intersecting arc at point n with m as the center and m ′ n ′ as the radius.

(7) Make the light OC from point O to point N. 。

∠COD is what you want.

37. Solution: In a triangular plate with angles of 45 and 30, the vertex and one side overlap, and an angle of 75 can be drawn. Similarly, the angle of105 can be drawn by using the angles of 60 and 45 in the triangular plate.

Six,

38. Solution: (2) The clipping part of the graph may be (3) and (5), (3) the clipping part of the graph may be (2) the graph, and (5) the clipping part of the graph may be (2) the graph.

39. Omission

(4) the answer

(1) Marking method (2) All object data are comprehensive, reliable and accurate; Need to spend a lot of manpower, material resources and financial resources (3)45405 copies 162 copies.

(4) The height of all girls in the second grade of junior high school in our school; The height of 60 female students in our school.

(5) Sampling survey (6)2 times and 7 times

(7)① What kind of ball games do students like? 2 classmates.

⑧ Number of balls that respondents like.

④ Questionnaire survey or interview survey.

(8) polyline

2.9— 14: BDD CAD

Iii. 15, (omitted)

16, (1)480 people (2) crossing Fushun Road and consciously taking the footbridge 55.3% 17, 120.

Answers to the midterm math exam in the first semester of grade seven.

1. Fill in the blanks (65438+ 0 for each blank, ***20 for each blank)

1、_ - 1 -3 6 __-8____-8____。 2, _ 9, -9 _ _ 1,-1 _ _ 3,-0.05m.

4._(-4)3_,-42_,_-(-3)2_; _(-3)2_ and _-(-3) 2 _ _ 5 _ _ 4x = 3x-7 _ _ 6，_ _ 2 _ _ 7. 1/30 _ _ 1/ 106544。 8._ 1.5 12× 106 _ _ 9.3x- 10。 -3 1 1.5 or 26, with a difference of 1, 2 and 6 respectively.

Second, multiple-choice questions (2 points for each small question, *** 18 points)

12.B 13。 D 14 A 15、D 16、B 17、D 18。 B 19、A 20、B

3. Calculation problems. 2 1. Write the calculation steps (5 points for each question, 20 points for * * *).

Solution: original formula =12+18-7-15 solution: original formula = 1×2+(-8) ÷4-4.

=30-22 =2-2-4

=8 =-4

Solution: Original formula =-× (-48)+× (-48)-× (-48) Solution: Original formula = 1 × (-) ×

=8-36+4 = 1/25

=-24

4. Solving equation: 22 (5 points for each question, ***20 points)

1.x = 2 ^ 2。 y = 2 ^ 3。 X= -3 4。 x= 1

Verbs (short for verb) solve problems.

23.( 1)(x-y)2 = x2-2xy+y2( 1)

(2) solution: the original formula =(53-23)2 =202 =400(2 points)

24. Solution: (1-80%)×20x= 1.6

x=0.4

25.( 1) What is the water level on Sunday? (2) Which day is the highest water level?

Solution: (1) 73.1+0.30+0.25-0.55+0.40+0.20-0.55+0.05 = 73.2m.

(2) Monday: 73.1+0.30 = 73.4; : Tuesday: 73.4+0.25 = 73.65 Wednesday: 73.65-0.55=73. 10.

Thursday: 73. 10+0.40=73.50, Friday: 73.50+0.20 = 73.70, Saturday: 73.70-0.55 = 73. 15.

Sunday: 73. 15+0.05 = 73.2m The water level is the highest on Friday.

26. Number axis abbreviation, the value range is (-2.5 2.5) open interval. The answer is not unique.

27. Solution: (1) The average value of five numbers in the cross box is equal to 15.

(2) Answer: The sum of these five numbers can be equal to 3 15.

Let the middle be X, then the top is X- 10, the bottom is X+ 10, the left is X-2, and the right is X+2.

X+X- 10+X+ 10+X-2+X+2 = 3 15 53

X=63 These five numbers are 6 1 63 65.

73

The tangent is 1 2 3 4 5.

Block number 4 7 10 13 16

28.

Solution: (2) If it is cut 100 times, * * cut out1+100× 3 = 301cube.

(3) If cutting for n times, * * * cuts out 1+3n small squares.

(4) Observing the graph, we can also get the rule that the side length of a square cut n times is 1/2n.

(9) Answer

Fill in the blanks

1.2.2 3.4.-25.-26.8 7. Red 8.09.610.110 or 40.

Second, multiple choice questions

1 1.B 12。 C 13。 D 14。 D 15。 B 16。 C 17。 C 18。 D 19。 B 20.B。

Third, calculation

2 1.- 18.

22.43.

23.(3 points), 30(3 points).

Fourth, solve the following problems

24.∠ 1 = ∠ 2 can be obtained from known conditions and are equal according to congruence angle.

If two straight lines are parallel, you can get. (4 points).

Because according to the fact that two straight lines are parallel and complementary,

You can get ∠ 3+∠ 4 = 180, so ∠ 4 = 180-85 = 95. (3 points)

25.( 1)5000-780-650+ 1250―3 10―420+240

= 4330 (yuan); (3 points)

(2) (780+650+1250+310+420+240) × 0.1%= 3.65 yuan (3 points).

Answer: (1) He has to return 4330 yuan to the bank after work; (2) The bonus he deserves this day is 3.65 yuan. (1 min)

26.( 1)60,4,200 1; (2 points for each space)

(2) .

A: By the end of 2004, the green area increased to 265,438+0% compared with the end of 2002. (2 points)

Final quality inspection volume a

I.1.d2.c3.c4.d5.a6.a7.d8.d.

2.9.-2, - 1 10.- 1, -2, -3, -4,-5; 1 1 1 1. 1 12.

13. 14., 15. 10 16.

Three. 17.-2 18.32

Four. 19.20.

Verb (abbreviation of verb) 2 1. Solution: Suppose the depositor deposits RMB, then,

∴

A: The depositor deposited 20,000 yuan.

22. Solution: If the middle step is the first step, then the whole ladder has steps.

According to the meaning of the question, you must

∴ .

∴ .

Answer: This ladder has 23 steps.

23. Solution: Get it through equality.

Again, yes.

And split it equally, so

24. Solution: There is a student in the science and technology group.

According to the meaning of the question, you must

,

.

A: There are two students in the science and technology group.

25. Solution: (1),

Kilograms of vegetables are put on the scale, and the pointer turns.

(2) (kg), * * * has kg of vegetables.

26. You can better see the change curve of the number of gold medals in the 5th China Olympic Games by choosing the broken line statistical chart, as shown in the figure below. The bar chart focuses on the number of gold medals in each session, while the plate chart focuses on the proportion of the number of gold medals in the fifth session to the total number of gold medals.

( 10)

A, 1, -302, two points determine a straight line 3, 1 4,114605,56, 12 2n+4.

7， 1 10 29′30″8，5cm 9，60 10，90 80km 1 1，32 12，40。

Ii. 13, C 14, D 15, A 16, B 17, A 18, A 19, C 20.

Three. 23, 24, =-3, 25, 26, (1), 3270 degrees (2) 16350 yuan from the perspective of rotation and overlooking.

4.27. Solution: Let the height of the mountain peak be m-1: 28,

There are still 2.6-=-2.2-4 points.

Solution = 600-6 points.

A: The peak height is 600 meters -7 minutes.

29. Solution: There are * * * classmates in grade 7-1.

According to the meaning of the question, there are: -4 o'clock.

Score = 360-6.

A: There are 360 people at level 7 * *-7 points.

30, won't give Xiao careless full marks-1.

The reason is: Xiao Careless didn't consider the problem comprehensively. He only considered the situation that OC falls within ∠AOB and OC falls outside ∠AOB (omitted)-4 points.

When OC falls outside ∠AOB ∠ AOC = ∠ AOB+∠ BOC = 85-7 points.

5. 3 1, (1) The sales in the first, second, third and fourth quarters were 240, 25, 15 and 220 respectively. (1) can be represented by a bar graph (omitted) (2)

(2) The total sales volume is 500 pieces; Sales in the first, second, third and fourth quarters accounted for 48%, 5%, 3% and 44% of the total sales respectively. (2 points)

Can be represented by pie chart (sketch) (2 points)

(3) As can be seen from the chart, the sales volume in the second and third quarters is relatively small, and the sales volume in the first and fourth quarters is relatively large. It is suggested to buy more down jackets in the peak season and transfer them to other goods or rent them to others in the off-season. (Only when the decision is reasonable) (2 points)

32, solution; (1) When buying a box of table tennis, the two preferential ways will pay the same-1 points.

According to the meaning of the question: 30× 5+(-5 )× 5 = (30× 5+5 )× 0.9-4 points.

Score = 20-5 points.

So when buying 20 boxes of table tennis, the two preferential ways are the same.

(2) When purchasing 15 boxes, Store A needs to pay 30× 5+( 15-5 )× 5 = 200 (yuan), and Store B needs to pay (30×5+ 15×5)×0.9=202.5. Because 200 < 202.5, when buying 15 boxes of table tennis, it is more cost-effective to go to a store. -Seven points.

When buying 30 boxes: a store needs to pay 30× 5+(30-5 )× 5 = 275 yuan; Store B needs to pay (30×5+30×5)×0.9=270 yuan. Because 275 > 270, when buying 30 boxes of table tennis, it is more cost-effective to go to B shop. -Nine points.

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