Counting Problem( Week 18 Evaluation) 1. It takes 6 minutes to cut a piece of wood into 2 pieces. How many minutes will it take to cut the wood into 6 pieces? 2. It takes a clock 12 seconds to chime 3 times. How many seconds will it take to chime 11 times? Assume that the lasting time of each chime can be neglected. 3. There are 3 red cards and 7 yellow cards in a box. At least, how many cards do you need to pick out of the box at the same time to make sure that there are two cards with different colors? 5. In a conventional clock with hour, minute, and second hands, how many times does the minute hand pass the hour hand between 09:00 AM and 01:00 PM in a day? 6. In the natural numbers from 1 to 100, how many times does digit '4' show up? 7. How many 3-digit numbers have the sum of the digits equal to 6? 8. A book has 200 pages numbered 1, 2, 3,... and so on. How many times does the digit 6 appear exactly once in the page numbers? 9. If you are asked to write down the natural numbers from 1 to 190, how many digits in total will be written? 10. If it is now 4 P.M., what time will it be 40 hours from now? |