Estimation means judging a useful approximate amount before measuring. The estimate does not need to be exact; it needs to be sensible enough to guide a decision or show up an answer that does not make sense.

Estimate from a reference

Use practical situations involving length, mass, capacity, time or cost. Ask the young person to compare the unknown amount with something familiar.

For example:

• a standard door is about two metres high;

• a bag of sugar weighs one kilogram;

• a mug holds roughly a quarter of a litre;

• a familiar journey takes about 20 minutes.

Before measuring a desk, filling a container or planning travel time, ask for a reasonable range and which reference informed it.

Measure and adjust

Check the estimate with the appropriate tool. Discuss:

• Was the estimate useful for the decision?

• Which feature was misleading?

• Which new reference should be remembered?

• Would a different unit make more sense?

Record only the reference amounts that are useful. A short list on a phone or in a planner can gradually build a bank of reference values.

Avoid treating an inaccurate first estimate as failure. The learning comes from comparing, measuring and revising. If the young person cannot interpret common scales or units, ask the maths teacher which units and scales to practise at home.