Name ——————————— Score
Students, the time has passed by half. Let's do it together. How much mathematical knowledge have you mastered? Come on!
First, choose with your heart: you can do it! (3 points for each question, ***30 points)
The reciprocal of 1 and -2 is ()
a、 1/2 B 、- 1/2 C 、-2 D、2
2, the following operation result is correct ()
a 、-22 = 16 B 、-(-2)2 = 4 C 、(- )3= - D 、(-2)3= -8
3. The result of calculating 2a-2(a+ 1) is ().
A.-2 b . 2 c .- 1d . 1 1
4, real number 0,-,π, 0.8080080008, medium, irrational number ().
1。
5. Rounding 50364 and keeping two significant figures is ().
a、5.04× 10？ 4 B、5.03× 104 C、5.0× 104 D、5000
6. If |a|=2 and |b|=5, then ab= ()
A, 10 B,-10 C, 10d, none of the above answers are correct.
7. On the number axis, the number represented by point A is 2, the distance between point B and point A is 3 units, and the number represented by point B is ().
A.5 B.-5 C.- 1 D.5 or-1
8. The integer whose absolute value is greater than 3 but not greater than 6 is ().
A.3 B.4 C.6 D.7
9. As shown in the figure, the rational numbers corresponding to the four points A, B, C and D on the number axis are integers A, B, C, D and C-2A = 7 respectively, so the origin should be ().
A，A，B，B，C，C，D，D。
10. Given that the real number satisfies, the maximum value of the following algebraic expression is ().
A.B. C. D。
Second, fill in patiently: you must be great! : (2 points for each blank, ***22 points)
1 1. The water level rises by 0.3 meters, which is recorded as +0.3 meters, and the water level drops by 0.4 meters, which is recorded as _ _ _ _ _ _ _ _ _ meters.
The arithmetic square root of 12. 9 is _ _ _ _ _ _ _.
13. Calculation: = _ _ _ _ _ _; ________ .
14. The coefficient of single item -A2BC is _ _ _ _ _ _ _ _; The frequency is _ _ _ _ _ _ _.
15. Every 30 minutes, a cell divides from 1 to 2 cells. After 2 hours, this cell can divide from 1 to _ _ _ _ _ _ _.
16. If A and B are reciprocal and C and D are antonyms, then 3ab+2c+2d = _ _ _ _ _ _ _.
17. Define the operation※ = (+), and calculate the value of 2※3 as.
18. Fold a rectangular piece of paper in half to get the crease as shown in the figure. (dotted line in the figure), continue to fold in half, each fold will be parallel to the last fold. After being folded in half for three times in a row, you can get a 30% discount, so you can get _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Third, calculate: you must be a strong person in learning! (The total score of this big question is ***48, please answer it carefully. )
19. Draw a number axis first, and then represent the following numbers on the number axis, arranged in the order from small to large, and use "
, 1, 4.5, 0, .
20. (This small question is 12 points) Calculate the following questions:
( 1)9- 13+ 16; (2) ;
(3) ; (4)
2 1, (6 points in this question) Solve the equation:
22. (6 points) Simplify before evaluating:
, where x =- 1 and y = 23.
23. (8 points in this question) The weight standard of a batch of goods per box is 2kg, and the quality inspector randomly checks 5 boxes with overweight, with quantity marked as "+"and shortage marked as "-",respectively marked as -0. 1, -0.2, +0.3, +0. 1 and +0.5.
24. (This small question is 10) As shown in the figure, there is a quarter circular lawn with the same radius at each corner of a rectangular square. If the radius of a circle is r meters, the width of a rectangle is a meter and the length is b meters.
(1) Use algebraic expression to express the area of open space;
(2) If the width of a rectangle is 200 meters, the length is 250 meters, and the radius of a circle is 10 meters, find the area of the square clearing. (π takes 3. 14)