Regrouping Sums Today

Overview

Students use Daily 3 routines and purposeful design activities to add 2-digit numbers with regrouping (making a new ten) using place value models, drawings, and explanations. The lesson builds toward strategies connected to the written method and the relationship between addition and subtraction.

Learning intentions

Students will be able to:

• Add two-digit numbers by adding tens and ones and regrouping when ones total 10 or more.
• Use concrete models (base-ten blocks) and drawings to show regrouping.
• Explain their reasoning for the regrouping step using place value language (tens, ones, compose/ten).
• Represent the strategy with a written addition equation.

Success criteria

• I can show regrouping with base-ten blocks and/or a drawing.
• I can tell how many tens and ones I end with after adding.
• I can write the correct sum and explain how I got it.
• I can use a strategy that makes sense (make a ten / add tens and ones).

Curriculum links

• Number and Operations in Base Ten: Add within 100 using concrete models/drawings and strategies based on place value, including composing a ten.
• Operations and Algebraic Thinking: Apply properties of operations as strategies to add and subtract (e.g., making an easier known sum).
• Operations and Algebraic Thinking: Use making ten and other strategies; connect strategy to a written method and reasoning.

Lesson structure (60 minutes)

1. 0–5 min · Launch (number talk). Teacher displays: 38 + 7; students show thinking with fingers or quick sketches, then share one strategy. Students: Think quietly, then turn-and-talk about how you could make a ten from the ones.

2. 5–15 min · Mini-lesson: “Build, trade, and write.” Teacher models 38 + 7 using base-ten blocks: build 38 (3 tens, 8 ones), then add 7 ones; when ones reach 10, trade 10 ones for 1 ten and continue. Students: Watch, then choral-repeat place value language (“I have ___ tens and ___ ones”; “I composed a ten”). Students record the equation: 38 + 7 = ___.

3. 15–45 min · Daily 3 stations (purposeful design, hands-on). Teacher sets up three stations and rotates every ~10 minutes; teacher conferences with the “Teacher table” group each round.

• Station A (Work on Your Own): Base-ten recording mats Teacher provides card sets with problems like 24 + 8, 35 + 6, 46 + 5 (each prompts regrouping at least once across the set). Students: Build with blocks on a mat, draw a quick sketch, then write the addition equation and a 1-sentence explanation.

• Station B (Partner Work): Make-a-ten strategy challenge Teacher gives partner cards where students must name what ten they will make (e.g., “Turn 7 ones into 2 to make 10” depending on the problem) and then find the total. Students: Discuss and demonstrate with blocks; agree on a reasoning sentence and check the sum.

• Station C (Teacher Table): Guided regrouping explanation Teacher uses a smaller set of problems and asks targeted questions: “Do we need to regroup? How do you know?” “What happens to the ones?” “How many tens do you have now?” Students: Solve with teacher prompts and practice explaining the trade into one more ten.

4. 45–55 min · Whole group share (compare strategies). Teacher selects 2 student examples (one fully correct, one with a common error such as forgetting the trade). Students: Explain what happened in the blocks and whether the regrouping was necessary; class agrees on the correct written equation.

5. 55–60 min · Exit ticket (quick check, no worksheets if possible). Teacher hands each student a small card with one problem (e.g., 27 + 9 or 48 + 6) and a tiny base-ten “show it” area. Students: Build or draw, write the sum, and circle the reasoning choice: “I regrouped because the ones made a ten.”

Resources

• Base-ten blocks (tens rods and ones cubes) for each student or shared sets
• Regrouping mats with place value areas (tens/ones) and writing lines
• Small problem card deck (2-digit + 1-digit within 100, with regrouping)
• Partner reasoning card prompts (sentence frames for explanations)
• Document camera or board space for modeling and comparing examples
• Exit ticket cards with space to show tens/ones quickly

Assessment

• Teacher observation during Daily 3: checks for correct regrouping (trade of 10 ones for 1 ten).
• Station feedback: listens for student explanations using place value terms and a correct written equation.
• Exit ticket: verifies sum accuracy and whether students correctly identify the need to regroup.

Differentiation

• Support:
• Provide sentence starters: “I grouped the ones to make ___.” “I traded ___ ones for 1 ten.” “Now I have ___ tens and ___ ones.”
• Offer a visual “compose a ten” cue card at stations.
• Enrichment:
• Challenge students to solve a second problem without rebuilding from scratch by using their previous model drawing.
• Ask for two different strategies (make a ten vs. add tens/ones) and compare.
• EAL/SEN:
• Allow students to explain using gestures and models first, then add a written sentence together.
• Keep numbers consistent in difficulty; reduce to 2-digit + 1-digit when needed before adding more variation.