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Grade 2 · Mathematics · 20 minutes

Arrays and equal groups

Draw three rows with four dots in each. Rows in an array can represent repeated addition.

Mr. S Teaches · Starter mini-lesson · elem-2-arrays-and-equal-groups

Learning objective

Explain and practice arrays and equal groups using the activity and evidence, then show the reasoning behind an answer.

Gather your materials

  • Paper and pencil
  • Counters, blocks or paper pieces
  • A ruler, clock model or grid when named in the steps

Use the items named in the teaching steps; paper models or adult-prepared photographs can replace physical equipment.

Common Core skill focus

2.OA.C.4

Use repeated addition for arrays with at most five rows and columns.

Read the official standard ↗

Code and grade verified 2026-11-03. This mini-lesson addresses a selected skill, not the entire standard.

Teach it step by step

  1. Draw three rows with four dots in each.
  2. Count each row to verify equal group size.
  3. Add 4 + 4 + 4.
  4. Turn the array and describe the new rows.

Watch, notice, discuss

Video choices for this lesson

2 choices

Preview a video, then choose what fits your learners. “Show to class” opens a larger view; use the player’s play and full-screen controls when you’re ready.

Teacher preview needed. Check the language, level and length before showing. YouTube may show ads or related videos.

After watching

Draw equal rows of dots. Write a repeated-addition sentence that matches your array.

An external player loads only after you choose Preview or Show to class. Playback connects to YouTube. Videos belong to their creators; availability and embedding can change.

Make the thinking visible

Example to work through together

3 rows of 4 total 12 dots. Turning the array gives 4 rows of 3, also 12.

Try the starter activity

Draw 3 rows of 4 dots; write 4 + 4 + 4.

Student practice

Draw 2 rows of 5 and 5 rows of 2; write a repeated-addition sentence for each.

Quick check for understanding

How many dots are there?

Sample answer and teacher guidance

Sample answer: 12

Listen or look for: 5 + 5 = 10 and 2 + 2 + 2 + 2 + 2 = 10.

Invite the learner to explain, demonstrate, draw or dictate their reasoning. Revisit a teaching step when the explanation is unclear.

Make it work for your learner

A little more support

Use counters on a grid to keep rows aligned.

An additional challenge

Find all rectangular arrays for 12 using at most 5 rows and 5 columns.