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Help me solve a few Olympic math problems
First, calculation. (Write down the main process. 4 points for each small question, ***8 points)

1, (78.6—0.786× 25 175 %× 2 1.4) ÷ 15× 1997

Fill in the blanks. (5 points for each small question, ***60 points)

1, there are dozens of apples, three numbers of three, two more, four numbers of four, two more, five numbers of five, two more. There are (62) apples in this pile.

2. After the fraction is decimal, the number at1993rd after the decimal point is ().

3. Observe the five formulas1+3 = 44+5 = 99+7 =16+9 = 2525+1= 36, and find out the rules, then the next formula is (36+65438).

4. There are two piles of coal, A and B. If 12 tons of coal is taken from pile A and put into pile B, the weights of the two piles of coal are equal. If 12 tons of coal is taken out from the second coal pile and put into the first coal pile, the weight of the first coal pile is twice that of the second coal pile. Two piles of coal A and B weigh () tons.

5. When 40 students do three math problems, 25 students correctly answer the first question, 28 students correctly answer the second question and 3 1 student correctly answer the third question, then at least _ _ _ _ people correctly answer the third question.

6. Among the three international friends, the gentleman wearing a white coat said, "The skin colors of the three of us are different. The color of the coat we wear is just the skin colors of the three of us, but everyone wears a coat that is different from his own skin color." The dark-skinned gentleman nodded again and again after hearing this. The yellow-skinned gentleman wore a _ _ _ _ _ coat.

7. There are five natural numbers, of which the first number is less than twice the second number, the second number is less than three times the third number, the third number is less than four times the fourth number, the fourth number is less than five times the fifth number, and the fifth number is less than 100, so the maximum value of the first number is _ _ _ _.

8. Put three red chopsticks, nine yellow chopsticks, 18 green chopsticks, two white chopsticks and 1 black chopsticks in a cloth bag, and touch at least _ _ _ _ to ensure that there are two pairs of chopsticks with the same color.

9. There are 20 rows of seats in the examination room. There are 20 seats in the first row, and each row has one more seat than the previous row. If candidates are allowed to sit at will, but not next to other candidates, the examination room can accommodate at most () candidates.

10, the surface area of a cuboid is 50 square centimeters, and both upper and lower sides are squares. If it can be cut into two cubes with equal volume, the surface area will increase by () square centimeters.

5. There are three boxes, and every two boxes are weighed together, weighing 63 kg, 65 kg and 66 kg respectively. The heaviest box is _ _ _ _ kilograms heavier than the lightest box.

12. Uncle Wang has a vegetable garden (as shown on the right), and he intends to use it.

The fence was enclosed. In order to know the length of the fence, he wants his daughter.

Xiaoying measured the circumference of this vegetable field. Xiaoying is the first among A, B and C,

Put a stake at five o'clock in D and E, and measure AB, BC and E respectively.

The length of DE, you can calculate the perimeter of this vegetable field. This vegetable garden

The circumference of is () meters.

3. As shown in the figure below, in the right-angled trapezoidal ABCD, AB = 15cm, AD = 12cm, and the shadow area is 15cm. What is the area of trapezoidal ABCD? (8 points)

Fourth, answer questions. (***32 points)

1.There are 282 books on the shelves A and B, and 3/4 on the shelf A and 5/9 on the shelf B are equal. How many books are there on each shelf? (8 points)

2. Yuhong Primary School originally planned to plant apricot, peach and pear trees *** 1500. After planting trees, when 3/5 of the total apricot trees and 30 peach trees are planted, 15 pear trees will be temporarily transported. At this time, the number of the remaining three trees is just equal. How many trees were originally planned to be planted? (9 points)