2. One day after the heavy snow, Xiaoming and his father measured the circumference of a round garden synchronously. They started from exactly the same direction. Xiao Ming's average stride is 54 cm, and Dad's average stride is 72 cm. Because their footprints overlapped, they returned to the starting point after a circle, leaving only 60 footprints in the snow. What is the circumference of this garden?
3. Party A and Party B walk in opposite directions from two places 1 100 meters apart. Party A walks 65 meters per minute and Party B walks 75 meters per minute. It takes 4 minutes for Party A to start. B took a dog and set out at the same time. The dog runs to a at a speed of 150 meters per minute. After meeting A, it immediately ran back to B, and then ran back to A until A and B met. How many miles did the dog run?
4. A ship is sailing at a speed of 20km per hour in still water. In a river with a water flow speed of 4km per hour, it takes 12.5h to get the distance from pier A to pier B. ..
5. Find a pattern to fill in the following numbers: 1, 4,9, 16, (), 36 ... 2,3,5,8,21 ...
6. There is a 45-meter-long runway with two colorful flags at both ends. The PE teacher asked to insert a colorful flag every 5 meters on this runway, and also needed colorful flags ().
7. One key opens one lock, and now eight keys and eight locks are all messed up. To pair again, try at most () times and at least () times.
8. My brother's age five years ago is equal to my sister's age three years later. When my brother was () years old, it was exactly three times my sister's age
9. From midnight to noon 12, the hour hand and minute hand overlap () times.
10. A piece of wood is 24 decimeters long. If you want to saw a 4-meter-long stick, you need 3 points for each saw, 2 points for rest after saw, and () points for all saws.
1 1. Wang Dong has a deposit in 50 yuan, Zhang Hua has a deposit in 30 yuan, and Zhang Hua wants to catch up with Wang Dong. Wang Dong deposits in 5 yuan and Zhang Hua deposits in 9 yuan every month. It will take () months to catch up with Wang Dong.
12. There were 164 people in the third grade, and 28 people participated in the art interest group. The number of people who participate in music interest groups is twice that of art groups, and the number of people who participate in sports interest groups is twice that of music groups. If everyone participates in at least one interest group and at most two interest group activities, then at least () people will participate in two interest groups.
13. One of the three students, Zhang San, Li Si and Wang Wu, did a good thing for the group while the others were away. Afterwards, the teacher asked who did the good deed. Zhang San said it was Li Si, Li Si said it wasn't him, and Wang Wu said it wasn't him. One of them told the truth, and the one who did good was ().
14. Li finished a story book in 12 days, but must finish it in 2 days. Li Ming reads four more pages than Wang Fang every day. This story book has () pages.
15. A three-digit number, the sum of the numbers on each digit is 15, and the number on the 100th digit is 5 less than the number on the single digit; If the unit and the hundred digits are reversed, the new number is 39 times less than the original number. Then the original three digits are ()
16. The cells in the figure below are all squares, and the * * * in the figure has a () square.
17. There are 20 coins with 2 cents and 5 cents in Qin Wang's savings box, totaling 76 cents, including () coins with 2 cents.