Choose any three by three square of dates on a calendar page...
Make a set of numbers that use all the digits from 1 to 9, once and
once only. Add them up. The result is divisible by 9. Add each of
the digits in the new number. What is their sum? Now try some other
possibilities for yourself!
What happens to the perimeter of triangle ABC as the two smaller
circles change size and roll around inside the bigger circle?
Six points are arranged in space so that no three are
How many line segments can be formed by joining the points in
If all the line segments are coloured either red or green prove
that there is a triangle all of whose sides are of the same