Build, Compare, Change

Overview

In this hands-on Phase 1 lesson, students count, build and compare towers of connecting cubes to 10, then model what happens when cubes are added or taken away. The lesson develops reliable one-to-one counting and early addition and subtraction through play, talk and concrete materials.

Learning intentions

• WALT count objects carefully, saying one number for each cube.
• WALT build and compare towers up to 10.
• WALT show what happens when cubes are added or taken away.
• WALT tell a partner how a tower changed.

Success criteria

• I can count my cubes once each and tell how many I have.
• I can make a tower to match a numeral card.
• I can say which tower is taller, shorter or the same.
• I can show and explain what changed when cubes were added or taken away.

Key vocabulary: count, number, numeral, tower, cubes, more, fewer, same, taller, shorter, add, take away, altogether, left.

Curriculum links

• Te Mātaiaho Mathematics and Statistics Phase 1, first six months: whole numbers 0–20 as a sequence, including counting forwards and backwards.
• Phase 1 early addition and subtraction: joining and separating quantities within 10 using concrete materials.
• Phase 1 mathematical practices: represent, compare, explain and use mathematical language.
• Mathsteasers resources support challenge and deeper mathematical thinking for learners ready to extend their reasoning.

Lesson structure (45 minutes)

1. 0–5 min · Welcome and counting hook. Teacher opens with the counting hook and learning intention slides, shows a small pile of cubes and asks, “How can we find out how many without missing any?” Students watch the teacher touch and move one cube for each number, then count the class together to 10, forwards and backwards as far as is secure.

2. 5–12 min · Explicit modelling. Teacher models making a tower of 4, placing each cube carefully, matching it to numeral card 4, and saying, “I counted four cubes, so my tower shows 4”; model a tower of 6 beside it and compare using taller, shorter, more and fewer. Students practise the actions in the air and rehearse the sentence, “___ has more/fewer than ___ because ___.”

3. 12–25 min · Tower-building investigation. Teacher places numeral cards 0–10 face down at each table and gives each pair cubes; display the instructions on tower investigation instructions and visual examples. One partner turns over a card and names it, while the other builds a matching tower; both partners count to check, compare with a previous tower and swap roles. Students may build several towers, order them from shortest to tallest and explain their thinking to a partner.

4. 25–34 min · Add and take away. Teacher gathers students with towers of 5 and models, “I add 2. Now I have 7,” then removes 3 and says, “I take away 3. Now 4 are left”; pause at each stage to count the cubes one-to-one and record the matching numerals on the tower recording sheet. Students use their own towers to respond to prompts such as, “Build 4. Add 1. How many now?” and “Build 7. Take away 2. How many are left?”

5. 34–40 min · Partner explain and check. Teacher displays partner talk prompts and comparison questions and listens to selected pairs. Students take turns being the Builder and Explainer: “I had ___. I added/took away ___. Now I have ___.” Partners check by physically adding or removing cubes and recounting the final tower.

6. 40–45 min · Exit check and share. Teacher gives each student a small set of cubes and completes a quick individual check: “Make 6. Add 2. How many?” followed by “Make 8. Take away 3. How many are left?” Students show the answer with cubes and tell or point to the matching numeral; finish with the reflection and goodbye slide and invite two students to share what changed.

Resources

• Connecting cubes, approximately 10 per student
• Numeral cards 0–10, one set per table
• the counting, modelling, investigation and reflection slide deck
• the tower recording sheet
• Large demonstration cubes or magnetic cubes
• Whiteboard and marker
• Individual mini-whiteboards or numeral cards
• Simple recording grid for teacher assessment
• Floor space or table trays for towers

Safety and management: Remind students that cubes are for building, not throwing or putting in mouths. Use table trays or defined building spaces, keep towers low, and count cubes back into containers before moving. Seat students where all can see the modelling; pair a confident counter with a learner needing support, while ensuring both children handle materials and talk.

Assessment

Use the following grid during the investigation and exit check. Record ✓ independently, P with prompting, or N not yet.

Student	Counts one-to-one to 10	Matches tower to numeral	Compares towers	Models add/take away	Explains change
1
2
3
4
5

Duplicate or continue the grid for all 25 students.

• During modelling, ask: “How do you know?” and look for touching or moving each cube once, rather than counting by sight or recounting inconsistently.
• During partner work, ask: “Which tower has more? How can you prove it?” and “What changed when you added/took away?”
• For the exit check, note the student’s final quantity, whether they can show the change concretely, and whether they explain independently or need a prompt.

Differentiation

• Support: Begin with 0–5, use a five-frame or teacher-built model, provide numeral cards with dot patterns, and use the sentence frame: “I had ___. I added/took away ___. Now I have ___.” Count alongside students, then gradually reduce help.
• EAL learners: Pair spoken words with gestures and visible towers; repeat vocabulary naturally and accept pointing, building or drawing before expecting a full oral explanation.
• SEN considerations: Offer larger cubes, a quieter workspace, extra processing time and a clear turn-taking routine. Limit the choice of cards and provide hand-over-hand modelling only where appropriate.
• Extension: Ask students to find two different ways to make 8, predict the result before adding or removing cubes, or build a tower that is 2 more or 2 fewer than a partner’s tower and justify the comparison.