1. Of the following statements about monomials, the correct one is ().

A. The coefficient is 3 and the degree is 2 b. The coefficient is 2 and the degree is 2.

C. the coefficient is, the degree is 3 d, the coefficient is, and the degree is 3.

2. In the following four plane figures, the one that cannot be folded into a rectangular box without a cover is ().

A B C D

3. A customer bought a commodity at a 20% discount, and paid 30 yuan less than the marked price, so he spent () on this commodity.

A.70 yuan B. 120 yuan C. 150 yuan D. 300 yuan

4. If so, then.

5. As shown in the figure, point A is on the ray OX, and the length of OA is equal to 2cm. If OA rotates 30 counterclockwise around point O, then the position of the point can be expressed by (2,30). If you continue to rotate 45 counterclockwise until, the position of this point can be represented by (,).

6. Assuming that the line segment AB=20cm, there is a point C on the straight line AB, BC=6cm, and M is the midpoint of the line segment AC, then

AM= cm .

7. The number of terraced classrooms in a school 1 row is 12. Starting from the second row, each row has one more seat than the previous row.

(1) Please fill in the appropriate algebraic expressions in the blanks in the table below:

Number of seats in line 65438 +0 Number of seats in line 2 Number of seats in line 3 Number of seats in line 4 Number of seats in line n

12

(2) It is known that the number of seats in row 15 is twice that in row 5. Find the value of a and calculate how many seats are there in row 2 1?

8. On the flat ground, there are several small cubes with the same side length of 10cm.

Pile up into a geometric figure, as shown in the figure.

(1) This geometry consists of a small cube. Please draw three views of this geometry.

Front view, left view, top view

(2) If yellow paint is sprayed on the surface of this geometry, of all the small cubes, only one side of the cube is yellow, only two sides of the cube are yellow, and only three sides of the cube are yellow. (3 points)

(3) If you still have some identical cubes at hand, how many more cubes can you add while keeping the top view and the left view unchanged? At this time, if you want to spray red paint on the surface of this geometry again, will the area to be painted increase or decrease compared with the original geometry? How much cm2 has it increased or decreased? (4 points)

Answer:

1, D 2, A 3, b 4,5, (2,75) 6,7 or 13.

7、( 1) ; ; …;

(2) 12+ 14 = 2:

Find the time =12+(21-1) × 2 = 52.

8、( 1) 10

Three-sided diagram

(2) 1、2、3

(3) You can put up to 4 small cubes.

400 more than before.