Exploring One Less

Learning Objectives

By the end of this lesson, children will be able to:

• Understand the concept of "one less" as taking away one from a group.
• Count backwards using numbers 1 to 10.
• Verbalise and demonstrate subtraction by physically removing one object from a set.
• Relate "one less" to their everyday experiences and use accurate mathematical language.

Linked National Curriculum (Early Years Foundation Stage – Mathematics):

• Number: Develop understanding of numbers to 10, counting actions or objects accurately and order.
• Numerical Patterns: Begin to recognise and describe simple patterns and relationships, including some basic subtraction concepts such as “taking away one”.
• Foundation Stage Early Learning Goal (Number): “Children count reliably with numbers from one to 20, place them in order and say which number is one more or one less than a given number.”

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Resources Needed

• Counting blocks or counters (minimum 20)
• Large number cards (1 to 10)
• Whiteboard and marker
• “Ten-frame” mats or trays for organising counters
• Visual aids showing numbers with one less (e.g., 5 with 4 crossed out, etc.)
• Storybook or puppet to introduce the scenario (optional for engagement)

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Lesson Structure (30 minutes)

1. Introduction & Engagement (5 minutes)

• Welcome students and introduce the focus: “Today, we are going to find out what ‘one less’ means!”
• Use a puppet or a friendly puppet character to pose a problem: “I have 5 apples, but I ate one. How many apples do I have now?”
• Show 5 counters, then physically remove 1, and count out loud with the class.
• Emphasise the phrase “one less” – repeat several times.

2. Guided Exploration (10 minutes)

• Distribute counters and ten-frame mats to pairs or small groups (ensure social distancing if needed).
• Teacher holds up number cards (e.g., 4, 7, 9). For each number:
  1. Students place counters to match the number on their ten-frame.
  2. Then remove one counter and say the new number aloud.
• Encourage children to say complete sentences: “If I have 7 counters and take one away, I have 6 counters. Six is one less than seven.”
• Circulate to observe and prompt with questions: “What happens if we take one away?” “How many are left?”

3. Independent Activity (8 minutes)

• Provide each child with a set of counters and number cards from 1 to 10.
• Children select a number card, count out that many counters, then take one away themselves.
• Ask them to verbalise their thinking: “I had __. I took one away, now I have __.”
• For children needing support, use pairing or adult guidance.

4. Consolidation and Discussion (5 minutes)

• Come together as a class and invite volunteers to share what they did.
• Use the whiteboard to model a few examples of numbers with one less, encouraging children to come up and physically remove counters.
• Reinforce mathematical vocabulary: “less,” “one less,” “take away,” “subtract.”
• Finish with a quick counting backwards chant from 10 to 1 to solidify the idea of decreasing numbers.

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Assessment Opportunities

• Observe children accurately “taking away one” and verbalising the correct number remaining.
• Use questioning during activities to assess understanding of the "one less" concept and counting backwards.
• Listen for appropriate use of mathematical language in spoken responses.
• Informal assessment based on engagement and ability to complete independent task successfully.

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Differentiation

• Support: For children who find counting difficult, use smaller numbers (1-5) and one-to-one adult assistance. Use physical guidance to help removing counters.
• Challenge: Encourage confident counters to explore “one less” starting from numbers above 10 or use story problems involving subtraction of one in their daily life contexts.

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Cross-Curricular Links and Enrichment Ideas

• Communication and Language: Encouraging children to describe their thinking improves full sentence use and vocabulary.
• Personal, Social & Emotional Development: Working in pairs builds social skills.
• Physical Development: Handling small objects sharpens fine motor skills.
• Storytelling: Introduce a simple story that involves “one less” for contextual understanding, e.g. “One Less Bunny” story game with counters.

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Teacher Reflection Notes

• Were children able to physically demonstrate and verbalise “one less”?
• Did the use of visual and tactile materials support learners well?
• Could all children count backwards confidently or was more support required?
• Think about incorporating number songs or interactive games next lesson to deepen understanding.

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This structured, hands-on approach ensures Year Reception children develop a strong foundational understanding of subtraction as “one less,” fully aligned with the Early Years Foundation Stage and National Curriculum expectations for early mathematics.