Parts and a whole

Children in many schools now draw a word problem before they solve it. The drawing is a bar: one long rectangle for the whole amount, cut into pieces for the parts.

The point of the bar is to show what you know and what you do not. If you know the whole and one part, the missing part is the rest of the bar, and you find it by taking the known part away.

Three questions do most of the work: what is the whole? What do we not know? What stays the same? Ask them before anyone reaches for a sum.