Build and Join Numbers

Overview

Tamariki explore adding two small whole numbers by partitioning each number into groups of ones. Through a playful kai-sharing context, they use counters, talk about their thinking and record simple number sentences. The activity builds on recognising small quantities and counting objects with one-to-one correspondence.

Learning intentions

• WALT use counters to add two small whole numbers.
• WALT partition numbers into groups of ones.
• WALT explain how we found the total.
• WALT play and learn cooperatively with others.

Success criteria

• I can make two groups of counters.
• I can join the groups and count the total.
• I can show my thinking with counters, drawings or a number sentence.
• I can take turns and listen to another person’s idea.

Curriculum links

• Mana Aotūroa / Exploration, Outcome 3: using a range of strategies for thinking, reasoning and problem solving.
• Mana Aotūroa / Exploration, Goal 3: learning strategies for active exploration, thinking and reasoning.
• Mana Tangata / Contribution, Outcome 3: using skills and strategies to play and learn with others.
• Mana Reo / Communication, Outcome 5: recognising and using mathematical symbols and concepts with enjoyment, meaning and purpose.

Lesson structure (25 minutes)

1. 0–3 min · Kai-sharing hook. Teacher shows a picture of two plates and asks, “If three berries are on one plate and two are on another, how many berries altogether?” Use the berry-sharing hook slide to reveal the groups, then invite tamariki to share quick estimates. Students look, talk with a partner and explain how they might find the total.

2. 3–7 min · Model partitioning. Teacher places three counters in one hoop and two in another, saying, “I partitioned five into three and two. I can join the parts to find the whole: 3 and 2 makes 5.” Model the language “part, part, whole” and the symbols 3 + 2 = 5 using the part-part-whole modelling slides. Students help count each part, join the groups and count the whole.

3. 7–15 min · Partner investigation. Teacher places tamariki in four pairs and gives each pair counters, two hoops and the build-and-join recording sheet. Give each pair a small addition prompt, such as 1 + 2, 2 + 2, 3 + 1 or 4 + 2. Students build both parts, join them, count the whole and record it by drawing counters or completing a number sentence. Partners take turns as the “builder” and “counter”.

4. 15–20 min · Solve and explain. Teacher pauses pairs and displays two new problems, such as 2 + 3 and 4 + 1, on the partner challenge slides. Ask, “What are the two parts? How could you prove the total?” Students solve with counters, drawings or fingers, then explain their strategy to their partner or another pair.

5. 20–23 min · Share thinking. Teacher invites two pairs to demonstrate different solutions, valuing practical, visual and verbal explanations. Students listen, compare strategies and use sentence frames such as “I made ___ and ___; altogether there are ___.”

6. 23–25 min · Plenary and assessment. Teacher gives each child a quick oral or practical problem, for example, “Make 2 and 1. How many altogether?” and revisits the final recap slide. Students build or draw the answer and complete the sentence, “___ plus ___ equals ___.”

Resources

• the number-partitioning slide deck
• the build-and-join recording sheet
• Small counters, such as bears, buttons or natural objects
• Hoops, plates or paper circles for two-part groups
• Large numeral and plus/equal symbol cards
• Pencils, crayons and clipboards
• Four trays or baskets for partner materials

Assessment

• Observe whether each child makes two distinct groups, counts each object once and combines the groups accurately.
• Listen for mathematical language, including “part”, “whole”, “altogether”, “plus” and “equals”; note whether tamariki can explain rather than only state an answer.
• Use the final practical problem as an exit check. Record who solves independently, who needs counters or adult prompting, and who is ready for larger numbers.

Differentiation

• Support: Begin with totals to 5 and use larger counters, two clearly coloured hoops and a part-part-whole mat. Model each step slowly and provide the sentence frame, “___ and ___ makes ___.”
• Language support: Pair children thoughtfully, use gestures while saying “part” and “whole”, and accept pointing, arranging objects, drawing or home-language explanations before inviting English mathematical vocabulary.
• Additional needs: Offer a quiet working space, reduce the number of counters, provide hand-over-hand support only when needed, and allow children to respond orally instead of writing.
• Extension: Invite confident tamariki to solve totals to 10, find two different partitions for the same whole, or create an addition problem for a partner without giving the answer.