2. Party A, Party B, Party C and Party D * * * processed 370 pieces. If the number of parts manufactured by Party A increases by 10, the number of parts manufactured by Party B decreases by 20, the number of parts manufactured by Party C is multiplied by 2, and the number of parts manufactured by Party D is divided by 2, and the number of parts manufactured by four people is exactly the same, how many parts has Party A actually processed? (70)
3. From 1 to 500, how many natural numbers * * * are there without the number 4? (324)
4. Divide two natural numbers X and Y, the quotient 3 is 10, and the sum of dividend, divisor and quotient remainder is 163. Find dividend and divisor. ( 1 15、35)
A math contest, the number of participants is about 380~450. As a result, the average score of all candidates is 76, the average score of boys is 75, and the average score of girls is 80. 1. How many boys and girls are there? (328,80)
6. A four-digit number is exactly equal to three times the remaining three digits after the first digit is removed. What is this four-digit number? ( 1500)
7. There is a two-digit number. If you add a 3 before it, you can get a three-digit number. Add 3 after it and you can get a three-digit number. The difference between these two three digits is 468. Find the original two digits. (85)
8. A six-digit natural number, move the last digit 7 to the first place, and move the other digits to the right one place in turn to get a new six-digit, which is four times the original six-digit, and find the original number. ( 179487)
9. Fill in one of 1~9 in each of the three numbers [], []7 and []48, so that the middle two digits are the average of the left and right digits, and find these three numbers. (6、77、 148)
10. There are several red, white and black balls, including 25 red and white balls, 3 white and black balls1,and 28 red and black balls. How many of these three balls are there? ( 1 1、 14、 17)
1 1. Someone went to buy textbooks and exercise books. There is one known textbook 10 yuan, one teacher 5 yuan, and 0 exercise book. 5 yuan, he has been buying 100 copies and spent 100 yuan. How many textbooks, reference books and exercise books did he buy? ( 1、9、90)
12. Output four-digit natural numbers, where the sum of each digit is 6 and the digits are different from each other, and count them. ( 1023、 1032、 1203、 1230、 1302、 1320、……、320 1、32 10, 18)
13. 1, 2, 3, 4, 5, 6 * * How many four-digit numbers can be formed? Output these data and count them. ( 1234、 1235、 1236、 1243、 1245、 1246、 1253、…、6542、6543，S=360)
14. Convert 100 yuan banknotes into 10 yuan, 5 yuan and 1 yuan banknotes ***20 sheets, output various conversion methods and count them. (4、 1 1,5; 8、2、 10; S=2)
15. Print "*" triangle: enter the natural number n (1 "n" 9) from the keyboard. According to the value of n, print out the corresponding "*" triangle. If n = 4, output
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