How long is a school bus? Estimation practice for grades 3 to 5

A fourth grader told me, with total confidence, that a polar bear weighs about ten pounds. He could do the unit conversions on his homework without a mistake. What he did not have was any feel for what the numbers meant, and no worksheet of conversions was going to give him that.

What the sheet looks like

The measurement estimation worksheet prints multiple-choice questions about roughly eighty everyday things: a paper clip, a bathtub, a school bus, a ten-year-old child. You choose Length and height, Weight, Capacity or Mixed, metric or US customary units, and 6 to 12 questions. The wrong answers are built to be instructive: the right number in the wrong unit, or the right unit but ten or a hundred times off. Choose the best unit asks which unit fits a thing, and a conversion chart can print at the bottom.

Why it works

• Because one wrong answer is always the right number with the wrong unit, a child cannot pick by recognizing the number. They have to think about whether a bus is 40 feet or 40 inches.
• The ten-times-off distractor catches kids who have a rough sense of size but no anchor. Is a bathtub 15 gallons or 40 or 400? You have to picture it.
• The objects are things the child has actually seen. There is nothing to estimate about a thing you cannot picture.

Who it suits

This is a grade 3 to 5 tool and does not go younger. A child needs to already know the units before estimating with them. Choose the best unit with Length and height is the gentlest entry point. For a child who has not measured much with a real ruler yet, the measure with a ruler sheet should come first.

Switch between metric and US customary now and then. The polar bear is the same size in both.