Creating and manipulating expressions and formulae

Write down a three-digit number Change the order of the digits to get a different number Find the difference between the two three digit numbers Follow the rest of the instructions then try to explain why this works.

Account of an investigation which starts from the area of an annulus and leads to the formula for the difference of two squares.

Think of a number, add one, double it, take away 3, add the number you first thought of, add 7, divide by 3 and take away the number you first thought of. You should now be left with 2. How do I know?

First of all, pick the number of times a week that you would like to eat chocolate. Multiply this number by 2...

For which values of n is the Fibonacci number fn even? Which Fibonnaci numbers are divisible by 3?

This pattern of six circles contains three unit circles. Work out the radii of the other three circles and the relationship between them.

After performing some operations, what number is your answer always a multiple of?

Can you find the value of t in these equations?

Can you find a rule which connects consecutive triangular numbers?

Can you work out the value of x in this 'power-full' equation?