Time: 90 minutes. Full score: 100.
I. Fill in the blanks (3× 20 = 60)
1, calculation: ()
2. Calculation: 2008× 20092009-2009× 20082008 = ()
3,4.15 hours = 4 hours () minutes.
4. There are five scores:,,,. The third number in descending order is ().
5. A cuboid block becomes a cube block if its length is reduced by 2 cm. The surface area of this cube is 96 square centimeters. It turns out that the volume of a cuboid block is () cubic centimeters.
6. The numerator of the three different simplest fractions are all prime numbers, and the denominator is less than 20. To make the sum of these three fractions as large as possible, these three fractions are ().
7. If the average age of four people is 30 years old, and none of them is less than 2 1 year old, then the oldest person is () years old.
8. Divide 14 by the sum of several natural numbers, and then find the product of these natural numbers. To make the product as big as possible, this product is ().
9. The solution of equation 1-= is = ().
10, 0, 1, 2, 3, 4 can form () three digits without repetition.
1 1, six students lined up to take pictures, * * * there are () different arrangements.
12, 4 o'clock face 10 minute, the angle between the hour hand and the minute hand is () degrees.
13, now a new operation is specified:, and then = ().
14. There are 40 kilograms of salt water with 8% salt. To make salt water with a salt content of 20%, it is necessary to add () kilograms of salt.
15, Wang Qiang multiplied the year of his birth by 3 1, then multiplied the date of birth by 12, and then added up, the total is 170, and Wang Qiang's birthday is ().
16, starting from the hour hand pointing to 4 o'clock, after () minutes, the hour hand coincides with the minute hand.
17, there is a five-dollar coin, four two-dollar coins and eight one-dollar coins. There are () different ways to withdraw 8 yuan money.
18. Among the natural numbers from 1 to 100, the number of () is not a multiple of 3 or 5.
19, the length, width and height of a cuboid are three consecutive even numbers, the volume is 960 cubic centimeters, and the surface area is () square centimeters.
20. If a commodity is priced at a profit of 20% and then sold at a discount of 8.8%, the actual profit will be 84 yuan. The cost of this commodity is () yuan.
Second, the calculation (5× 2 = 10)
( 1) (2) ×[2. 1 7÷( )]
Third, the application problem (5× 6 = 30)
1. There is 30 kilograms of salt water with a salt content of 25%. Now, add clean water. How much water is needed to reduce its content to 15%?
2. A commodity sells for 4 yuan according to the profit of each piece in 5 yuan, which is as much as 3 yuan according to the profit of each piece in 20 yuan. What is the cost of this commodity?
3. As shown in the figure, the area of trapezoidal ABCD is 45 square centimeters, the bottom AB = 10 centimeters, the height is 6 centimeters, and the area of triangular DOC is 5 square centimeters. Find the area of triangle AOB.
A factory has three workshops. The ratio of the first workshop to the second workshop is 2: 3, and the ratio of the third workshop to the total number of employees in the factory is 1: 3. It is known that the first workshop is 200 less than the second workshop. How many people are there in this factory?
5. For a project, it takes 10 hour for Party A to complete it alone, 15 hour for Party B to complete it alone, and 20 hours for Party C to complete it alone. Now the three of them work together. In the middle, A stopped work for several hours because of something, and it was finished in six hours. How many hours does Wen Jia stop working?
6. The letters A, B, C, D, E, F and the numbers 1, 9, 9 and 3 are changed in the following order:
A, b, c, d, e, f, 1, 9, 9, 3 (primitive)
B, C, D, E, F, A, 9, 9, 3, 1 (first change)
C, D, E, F, A, B, 9, 3, 1, 9 (second change)
D, e, f, a, b, c, 3, 1, 9, 9 (third change)
…… …… ……
Q: How many times will letters and numbers change back to their original order?
I don't understand Chinese.