Think of a number and follow the machine's instructions... I know what your number is! Can you explain how I know?
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?
Choose any four consecutive even numbers. Multiply the two middle numbers together. Multiply the first and last numbers. Now subtract your second answer from the first. Try it with your own numbers. Why is the answer always 8?
My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?
We can show that (x + 1)² = x² + 2x + 1 by considering the area of an (x + 1) by (x + 1) square. Show in a similar way that (x + 2)² = x² + 4x + 4
If you take a three by three square on a 1-10 addition square and multiply the diagonally opposite numbers together, what is the difference between these products. Why?
Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?
A country has decided to have just two different coins. Which totals can be made? Is there a largest total that cannot be made? How do you know?
Think of a number and follow my instructions. Tell me your answer, and I'll tell you what you started with! Can you explain how I know?
