Mathematics
Advanced
50 mins
Teacher/Student led
Learning Goals
Learning Outcomes
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+80 XP
What you need:
IWB/Projector/Large Screen

Finding the Missing Number

Learn to find a missing number when you know the whole and one part. Use bond diagrams to work out what's hiding in the box, then check your answer is correct.

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    1 - Getting Started ~4 mins

    Key point

    Look at this: □ + 4 = 10. The box is hiding a number. Some counters are covered up, and 4 more are on show, and together they make 10.

    Illustration for Getting StartedHow many do you think are hiding under the box? What made you say that number?

    👇 Mark your steps as done as you complete them.

    +5 XP

    2 - Watch and Notice ~9 mins

    Each bond has a whole up top and two parts below. When one part is hidden, we already know the whole and the other part, so we can work out what is missing.

    The last one is different, so watch it carefully. Read □ − 2 = 6 as: a whole, take away 2, leaves 6. So 6 and 2 are the two parts, which means the box must be the whole. Now we join the parts to find it.

    👇 Mark your steps as done as you complete them.

    +10 XP

    3 - Try It Together ~11 mins

    Key point

    We set each sum on the bond one at a time and step the empty part up together until the whole circle lights up. Today's sums: □ + 4 = 9, then □ + 2 = 7, then □ + 6 = 11, then □ − 4 = 3. Watch the last one — the box is not a part there, it is the whole.

    Fill the missing part

    +15 XP

    4 - Solve It in Your Copy ~2 mins

    COPYBOOK MOMENT

    In your maths copy, solve □ + 5 = 12 and □ + 6 = 14. Write the missing number in the box, then write the full true sentence underneath each one.

    +10 XP

    5 - Class Challenge ~8 mins

    Today's practice bonds — find the missing number in each:

    • whole 9, one part 2
    • whole 15, one part 7
    • whole 13, one part 5
    • parts 8 and 3 — this time the whole is hidden
    Key point

    Ask yourself first: is the box a part, or the whole?

    Set the missing circle, then tap Check.

    Find the missing number

    +15 XP
    Pupil practice
    Module 10 · Algebra: Patterns, Rules and Number Sentences Algebra
    Lesson 121 · Finding the Missing Number
    Download Activity Book page (PDF)
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