Odd Even Numbers

Overview

This is lesson 1 of 16 in Mastering Addition and Subtraction. In a low-variance, hands-on lesson, four students build, sort and explain odd and even numbers using counters, with examples connected to everyday situations.

Curriculum links

• Recognise, represent and order numbers using concrete materials, numerals and visual representations.
• Develop understanding of odd and even numbers through grouping objects into pairs.
• Identify and describe patterns in number sequences and explain simple mathematical reasoning.
• Use mathematical language to communicate strategies, representations and conclusions.

Learning intentions

Students will:

• Explore what makes a number odd or even.
• Build numbers with counters and group them into pairs.
• Recognise that even numbers can be shared into equal pairs, while odd numbers have one left over.
• Identify odd and even numbers in familiar contexts.
• Explain their thinking using concrete materials, drawings and mathematical language.

Success criteria

• I can make equal pairs with counters.
• I can identify whether a number is odd or even.
• I can explain that an even number has no counters left over.
• I can explain that an odd number has one counter left over.

Lesson structure (45 minutes)

1. 0–5 minutes – Welcome, routine and hook Display the learning intention and briefly explain the consistent lesson routine: Watch it, Build it, Say it, Show it. Open with the odd-or-even hook slide and ask: “Can four students share seven counters equally, with no one missing out?” Allow students to predict without correcting immediately. Seat students where materials are visible and provide a simple visual schedule. Use short instructions, wait time and praise for attending, explaining and taking turns.

2. 5–12 minutes – Explicit teaching: making pairs Use counters to build 2, 4, 5 and 6. Model placing counters in pairs from left to right. Think aloud: “Four makes two equal pairs, so four is even. Five makes two pairs with one left over, so five is odd.” Refer to the pairing demonstration slides. Introduce the terms odd, even, pair, equal and left over. Students repeat the sentence stems: “___ is even because…” and “___ is odd because…”.

3. 12–23 minutes – Guided sorting with concrete materials Give each student a small tub of counters and numeral cards showing numbers from 0 to 20. Students take turns selecting a card, building the number and arranging the counters into pairs. They place the card in an Odd or Even group. Use the sorting activity instructions to show the three steps: build, pair, sort. Prompt students to check one another respectfully: “Do you agree? How can we prove it?” Include zero and discuss that zero is even because it can be arranged into equal pairs with none left over.

4. 23–32 minutes – Everyday number investigation Present familiar examples through the everyday examples slides: pairs of shoes, wheels on a bicycle, students sitting in pairs and objects shared between two people. Students decide whether each quantity is odd or even, then demonstrate using counters or a quick drawing. Ask: “What do you notice about the numbers in the even group?” Guide students to notice the repeating pattern in the ones digits: 0, 2, 4, 6 and 8. Avoid relying on the pattern alone; reinforce that pairing is the reason.

5. 32–40 minutes – Independent recording and teacher check Distribute the odd and even numbers worksheet. Students complete a short set of build-and-classify questions, draw pairs for selected numbers and explain one answer using a sentence stem. Students may continue using counters. Confer individually with each student: ask them to build one odd and one even number and explain the difference. For students ready for challenge, include numbers beyond 20 and ask them to predict from the ones digit before checking with counters.

6. 40–45 minutes – Review and exit response Return to the review and exit prompt. Each student chooses a number, builds it, and tells the group whether it is odd or even and why. Revisit the opening question about seven counters and invite students to revise their prediction. Finish with the shared statement: “Even numbers make equal pairs. Odd numbers make equal pairs with one left over.” Collect worksheets and note each student’s level of independence.

Resources

• the odd and even numbers slide deck
• the odd and even numbers worksheet
• Counters, linking cubes or small classroom objects
• Numeral cards from 0 to 20
• Two labelled sorting hoops, mats or trays: Odd and Even
• Individual workspaces or small trays
• Visual schedule and first–then prompt
• Pencils, coloured pencils and erasers

Assessment

• Observe whether each student pairs counters accurately and classifies numbers correctly.
• Listen for explanations using odd, even, pair, equal and left over.
• Review the worksheet for accurate classifications, representations and explanations. Record whether support was needed, particularly for zero and numbers above 10.

Differentiation

• Support: use numbers from 0 to 10, larger counters and a pair-by-pair modelling prompt. Provide the sentence stems and allow students to point, build or draw before speaking.
• Support for ADHD and Autism: keep the four-step routine visible, give one instruction at a time, minimise materials on the desk and provide planned movement during card selection.
• EAL/D and communication support: pair spoken words with numeral cards, gestures and visual examples; accept drawing, pointing or using a communication device as evidence of understanding.
• Extension: use numbers to 100, ask students to predict odd or even from the ones digit, and investigate whether adding 2 changes the odd/even classification.