Arrange the numbers 1 to 6 in each set of circles below. The sum of each side of the triangle should equal the number in its centre.
Use cubes to continue making the numbers from 7 to 20. Are they sticks, rectangles or squares?
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?
If you don't have a partner to work with, you could use the interactivity below. The computer selects one digit at random. You must then choose a digit to make the largest possible two-digit even number or largest possible two-digit odd number.