1. As shown in the figure, there are two regular hexagons with the same size in the parallelogram, so the shadow area accounts for () of the parallelogram area.
(A) 1/2(B)2/3(C)2/5(D)5/ 12
2. Two paper tapes, 23cm long and 15 cm short. After cutting two paper tapes with the same length, it is required that the length of the remaining two paper tapes should not be less than twice the length of the shorter paper tape, so the cut length should be at least () cm.
(A)6 (B)7 (C)8 (D)9
There are several goldfish in the two ponds, the number is the same. Liang Liang and Hong Hong had a fishing competition. When the goldfish in the first pond were fished out, the ratio of the number of goldfish caught by Liangliang and Honghong was 3: 4. After catching the goldfish in the second pond, Liangliang caught 33 more goldfish than the first pond, and the ratio of the number of goldfish caught by Honghong was 5: 3. Then there are goldfish () in each pool.
1 12(B) 168(C)224(D)336
4. Remove two numbers from 1/2, 1/3, 1/4, 1/5 and 1/6, so that the sum of the remaining three numbers is closest to 6/7, and the two numbers removed are ().
(A) 1/2， 1/5 (B) 1/2， 1/6 (C) 1/3， 1/5 (D)
5. The smallest natural number with exactly 20 factors is ().
120 240(C)360(D)432
6. The large square grid as shown in the figure is paved with 8 1 small squares of1cm2, and B and C are two grid points. If you please mark a point A in other grids so that the area of △ABC is exactly equal to 3 square centimeters, there are () such points * * *.
(A)6 (B)5 (C)8 (D) 10
Fill in the blanks (score 10 for each small question, out of 40)
7. If the value of the formula is n/m, then the value of m+n is.
8. "Low-carbon life" starts from now on, starting from me. It is estimated that 1 ha deciduous broad-leaved forest can absorb carbon dioxide 14 tons per year. If the refrigeration temperature of each air conditioner is raised to 27℃ on the basis of 26℃ advocated by the state, the corresponding annual carbon dioxide emission reduction is 2 1kg. This emission reduction in only one city is equivalent to the carbon dioxide absorbed by 25,000 hectares of deciduous broad-leaved forest throughout the year; If each family has three air conditioners, there are about 10 thousand families in this city. (Keep integer)
9. Choose nine numbers from the ten numbers of 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 to form a two-digit number, a three-digit number and a four-digit number, so that the sum of these three numbers is equal to 20 10, then the unselected numbers are.
10. The picture on the right shows the toy train track. There is an orbit change switch at point A, which can be connected to B or C. The circumference of small circular orbit is 1.5m, and that of great circular orbit is 3m. At the beginning, A is connected with C, and the train starts from point A and moves clockwise on the track. At the same time, the track transfer switch switches the track connection every 1 minute. If the speed of the train is 10 meter per minute, it takes seconds for the train to return to point A for the first time 10.
answer
1.A
2.B
3.B
4、D
5、B
6、C
7、50
8、556
9、6
10、 126