Arrays and Equal Groups
Count the rows, count the columns, find the total.
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
Seeing repeated addition as rows and columns — the groundwork for multiplication.
The array is the representation that carries children from repeated addition into multiplication, and later into the area model and volume. Introducing it in grade 2 means grade 3 multiplication has something to stand on besides memorisation.
- The underlying idea
- The array turns repeated addition into a two-dimensional structure.
- Where this sits in Illustrative Mathematics
- 2nd grade Unit 8: Equal Groups
- Sources
- Illustrative Mathematics / Kendall Hunt (2024) · youcubed et al. (2015) · Fyfe et al. (2014) all references →
Related measured skill: ALPACA · Early operations. What this means