Water Use Math Challenge

Children measure how much water actually goes onto one garden bed across a week, then work out the weekly and monthly totals, then propose a way to cut it.

The maths is unit conversion, averages and percentage change, which is standard grade five content. The difference is that the numbers are theirs and the conclusion is actionable. A class that discovers its own bed uses 84 litres a week and then reduces it to 60 has done real work.

The sheet includes the recording table, the calculation frames, and a proposal box. Mulching is the answer most groups arrive at, and it works, so let them find it rather than telling them.

One honest note. If you water with a hose, this is hard to measure. Switch to buckets for the week of the investigation. The inconvenience is part of what makes the number real.