What happens when you add three numbers together? Will your answer be odd or even? How do you know?
Use the interactivities to fill in these Carroll diagrams. How do you know where to place the numbers?
Try out this number trick. What happens with different starting numbers? What do you notice?
Four bags contain a large number of 1s, 3s, 5s and 7s. Can you pick ten numbers from the bags so that their total is 37?
A hundred square has been printed on both sides of a piece of paper. What is on the back of 100? 58? 23? 19?
This problem challenges you to find out how many odd numbers there are between pairs of numbers. Can you find a pair of numbers that has four odds between them?
