Counting Problem( Week 18 Practice) 1. It takes 6 minutes to cut a piece of wood into 3 pieces. How many minutes will it take to cut the wood into 10 pieces? 2. There are 8 red cards and 5 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? 3. In a conventional clock with hour, minute, and second hands, how many times does the minute hand pass the hour hand between 06:00 AM and 07:00 AM in a day? 4. In the natural numbers from 1 to 100, how many times does digit '1' show up? 5. A book has 400 pages numbered 1, 2, 3,... and so on. How many times does the digit 1 appear exactly once in the page numbers? |