Can you find a way of counting the spheres in these arrangements?
The Number Jumbler can always work out your chosen symbol. Can you work out how?
In this 100 square, look at the green square which contains the numbers 2, 3, 12 and 13. What is the sum of the numbers that are diagonally opposite each other? What do you notice?
Can you find pairs of differently sized windows that cost the same?
Think of a number and follow the machine's instructions... I know what your number is! Can you explain how I know?