What Are Factors?

How do we work out the factors of a number, for example 20?

Well, if we can imagine a rectangular window made up of 20 panes of glass, how many different ways can this window be constructed?
We could construct this window using 2 rows of 10 panes. The result would be a rectangular window with 20 panes. What this means is that both 2, and 10 are factors of 20. Why? Because 2 x 10 = 20.
How else might we construct this window? Could we construct this window using 3 rows? If so, 3 would be a factor of 20.

Explore some of the different ways we can construct a 20-pane window and thus find the factors.
Once completed, try windows with different numbers of panes and see what you find.