Mathematics · Year 2

Active learning ideas

Adding Two-Digit Numbers (With Regrouping)

Active learning works well for this topic because physical manipulation of tens and ones lets students experience the shift of value when regrouping, making abstract place-value rules concrete. Students build confidence by touching and moving blocks, then connect that tactile understanding to written algorithms through guided reflection.

• ACARA Content Descriptions
• AC9M2N03

• 25–40 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Stations Rotation
• 30 min · Pairs

Manipulative Mats: Tens and Ones Addition

Provide mats divided into tens and ones columns with base-10 blocks. Students build two addends, combine ones, regroup ten ones into a tens rod, then record the equation and sum. Pairs discuss and justify the regrouping step before clearing for the next problem.

Justify why regrouping is necessary when the sum of the ones digits is ten or more.

Facilitation Tip

During Manipulative Mats, circulate and ask each pair to verbalize the count of tens and ones before and after regrouping to reinforce conservation of number.

What to look for

Provide students with two addition problems: one without regrouping (e.g., 23 + 14) and one with regrouping (e.g., 27 + 15). Ask students to solve both and write one sentence explaining the difference in how they solved the second problem compared to the first.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 02

• Stations Rotation
• 40 min · Small Groups

Stations Rotation: Regrouping Challenges

Set up stations with place value charts, number lines, and word problems requiring regrouping. Small groups spend 8 minutes per station solving and explaining their strategy aloud. Rotate and compare results as a class debrief.

Analyze the steps involved in regrouping during addition.

Facilitation Tip

In Station Rotation, position the regrouping station next to the non-regrouping station so students compare the processes side by side.

What to look for

Write a two-digit addition problem requiring regrouping on the board, such as 38 + 25. Ask students to show you their answer using base-ten blocks or by drawing. Observe if they correctly represent the regrouping of ten ones into one ten.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 03

• Stations Rotation
• 25 min · Pairs

Partner Relay: Addition Races

Pairs line up with whiteboards. One partner solves the ones column of a card problem and passes to the other for tens and regrouping. First pair to finish five problems correctly wins; switch roles midway.

Design a strategy to double-check an addition problem that involved regrouping.

Facilitation Tip

Set a 90-second timer for Partner Relay to keep energy high and prevent rushing past place-value checks.

What to look for

Pose the question: 'Imagine you are explaining to a friend why we write the '1' above the tens column when adding 27 + 15. What would you say?' Listen for explanations that reference exchanging ten ones for a ten.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

Activity 04

• Stations Rotation
• 35 min · Small Groups

Real-Life Shop: Money Addition

Use play money in tens and ones. Small groups add prices from shopping lists, regrouping coins into notes as needed. They check totals by recounting and record final receipts.

Justify why regrouping is necessary when the sum of the ones digits is ten or more.

What to look for

Provide students with two addition problems: one without regrouping (e.g., 23 + 14) and one with regrouping (e.g., 27 + 15). Ask students to solve both and write one sentence explaining the difference in how they solved the second problem compared to the first.

• Remember
• Understand
• Apply
• Analyze
• Self-Management
• Relationship Skills

A few notes on teaching this unit

Teach this topic through a gradual release model: start with explicit modeling using base-ten blocks, move to guided practice with think-alouds, and finish with independent problem solving. Research shows that students who physically exchange blocks before writing the algorithm develop stronger mental models. Avoid rushing to the written form; let the blocks anchor the concept first.

Students will accurately add two-digit numbers with regrouping, explain why exchanging ten ones for a ten is necessary, and apply double-check methods independently. You’ll see them justify steps using place-value language and correct their own work when errors occur.

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Watch Out for These Misconceptions

• During Manipulative Mats, watch for students who stack ten ones as a single unit without exchanging them for a ten rod.

  Pause the pair and ask, 'If these ten ones were real 1c coins, how would we trade them for a 10c coin?' Guide them to physically exchange the blocks while recounting tens and ones aloud.

• During Station Rotation, watch for students who assume regrouping only happens when the sum is exactly ten.

  At the regrouping station, have them test sums of 11, 12, and 13 ones, recording each decomposition as '1 ten and _ ones' to see the pattern across all sums ten or higher.

• During Partner Relay, watch for students who skip the regrouping step and write the total ones without adjusting the tens column.

  As they arrive at the regrouping checkpoint, hand them a dry-erase marker and ask, 'Where do the extra ones go?' Require them to cross out and write the new ten above the tens column before proceeding.

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Methods used in this brief

• Stations Rotation