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?
Suppose we allow ourselves to use three numbers less than 10 and
multiply them together. How many different products can you find?
How do you know you've got them all?
Investigate the different shaped bracelets you could make from 18
different spherical beads. How do they compare if you use 24 beads?
$462$ is the product of two consecutive numbers. These numbers
are $21$ and $22$, because $21 \times 22 = 462$.
Now try this.
$56 406$ is also the product of two consecutive numbers. What
are these two numbers?