Number Bonds and Counting

Overview

This 15-minute focused session targets Year 1 students, supporting their fluency in number bonds to 20 and 100, and counting in 2s, 5s, and 10s, fully aligned with the National Curriculum (England, Year 1 - Number - Number and Place Value and Addition and Subtraction). The session introduces addition and subtraction of 11 and 10 using concrete visual aids and mental strategies, embedding place value understanding and number sense through interactive activities.

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Curriculum Links

Mathematics - Number – Year 1 (England National Curriculum)

• Number and Place Value:
  • Recognise the place value of each digit in a two-digit number (tens, ones).
  • Count in steps of 2, 5 and 10 from 0, forwards and backwards.
• Addition and Subtraction:
  • Add and subtract one-digit and two-digit numbers to 20, including zero.
  • Read, write and interpret mathematical statements involving addition (+) and subtraction (−).

Key Learning Objective:

• Use number bonds to 20 and 100 to efficiently add and subtract 10 and 11 mentally.
• Understand and use the 100 square to add and subtract 10 and 1.
• Practise counting in 2s, 5s and 10s fluently forwards and backwards.

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Learning Outcomes

By the end of this session, pupils will:

• Confidently recall number bonds to 20 and 100.
• Count forwards and backwards in 2s, 5s and 10s (verbally and using visual aids).
• Add and subtract 10 and 11 using mental strategies and the 100 square.
• Demonstrate understanding of the "Robot Walk" method for subtraction on a 100 square.
• Use whiteboards and the 100 square for hands-on practice.

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Resources

• Individual whiteboards and dry wipe pens (for each child)
• 100 squares (individual laminated copies for each child or projected on the board)
• Visual number bond charts (to 20 and 100)
• Printed ‘Robot Walk’ illustration (showing movement up one row and left one square on 100 square)
• Counters or small objects (optional for added kinaesthetic practise)

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Lesson Breakdown

1. Quick Recall and Counting Warm-Up (4 minutes)

• Start with a brisk flash of number bonds to 20 and 100 using visual cards or charts (e.g., 10+10=20, 15+5=20, 50+50=100). Ask children to chorus or pair whisper answers for engagement.
• Quickly practise counting forwards and backwards in 2s, 5s and 10s with the whole class. Use visual clues or a number line. Encourage children to join in confidently.

2. Introducing +11 and -11 Using Mental Strategies (6 minutes)

• Write the number 25 on the board. Model:
  1. Subtract 10: 25 - 10 = 15
  2. Subtract 1 more: 15 - 1 = 14
• Emphasise the decomposition strategy (breaking 11 into 10 + 1) and encourage children to verbalise the steps. Repeat with 11 +, showing addition broken down as +10 then +1.
• Do a few examples with different starting numbers (e.g., 32, 40, 19), using the whiteboards for children to write their answers.
• Introduce the "Robot Walk" concept: Explain that to subtract 11 on a 100 square, the "robot" moves UP one row (subtract 10) and LEFT one square (subtract 1). Show this visually with the ‘Robot Walk’ diagram.
• Give pupils laminated 100 squares on their tables. Call out numbers and demonstrate the robot walk together.

3. Independent Practice with Whiteboards and 100 Squares (5 minutes)

• Pupils work individually or in pairs on whiteboards with a 100 square visible.
• Quick fire rounds of:
  • HAS: Adding and subtracting 11 (e.g., 22 + 11, 44 - 11)
  • MAS: Subtracting 11 (e.g., 37 - 11)
  • LAS: Adding and subtracting 10 (e.g., 52 + 10, 63 - 10)
• Teacher circulates, supporting pupils who need assistance.

4. Plenary and Assessment (Optional extra 2 minutes if possible)

• Invite a few pupils to explain how they subtract 11 using the robot walk to the rest of the class.
• Conduct quick, informal questioning to check children’s understanding and confidence in recalling bonds and using the 100 square.
• Note any common difficulties for follow-up support.

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Differentiation

• Support: Use counters or fingers to visualise the +1 or -1 step. Provide one-to-one support with whiteboards and 100 square for children needing extra help.
• Extension: Challenge confident learners to add and subtract multiples of 11 or to explain number bonds to 100 mentally.

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Reflection for Teachers

• Were pupils able to practically apply the decomposition strategy for adding and subtracting 11?
• Did the ‘Robot Walk’ visual aid help solidify understanding of the 100 square movement pattern?
• Plan follow-up activities using 100 squares to reinforce place value and subtraction/addition skills.

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This lesson not only targets key Year 1 objectives but uses creative visual strategies and concrete resources to deepen pupils’ numerical fluency, thinking skills, and confidence with mental addition and subtraction around the number 10 and 11.