Measure and Chart
How long is it? And what does the chart tell you?
For grown-ups
- How long: 10 to 15 minutes is plenty. Short and frequent beats long and occasional — the early-numeracy trials with the largest effects ran eight weeks or less.
- When they get one wrong: the page shows the working. Read it together rather than moving straight on. Feedback that explains is worth several times more than feedback that only marks right or wrong, and that gap is wider in maths than in any other subject.
- Not timed: thinking time is the point of a book. Let silences run.
- Print it too: doing the same problems on paper a few days later is worth more than doing twice as many today.
What this practises
Measuring length in units, and reading a bar chart to compare and total.
Required grade-2 coverage, and included on that basis rather than as an evidence claim — the WWC guidance on measurement and data is weak. It is framed to lean on what does have support: reading a bar off a scaled axis is a magnitude judgement, and comparing two bars is the same comparison the number work practises.
- The underlying idea
- A bar chart is a set of number lines standing up. Reading one is a magnitude comparison with a scale attached.
- Where this sits in Illustrative Mathematics
- 2nd grade Unit 3: Measuring Length · 2nd grade Unit 6: Geometry, Time, and Money
- Sources
- Illustrative Mathematics / Kendall Hunt (2024) · Institute of Education Sciences / What Works Clearinghouse (2021) all references →
Related measured skills: ALPACA · Early operations, MagPI · Number comparison. What this means