Place four pebbles on the sand in the form of a square. Keep adding as few pebbles as necessary to double the area. How many extra pebbles are added each time?
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!
Is there an efficient way to work out how many factors a large number has?
Simplify the game by choosing a smaller target and working out a
Investigate complements of $6$.
Play the game against the computer and think about the