Mathematics
Intermediate
50 mins
Teacher/Student led
+80 XP
What you need:
IWB/Projector/Large Screen

Finding a Fraction of a Quantity

Learn to find a fraction of a quantity by dividing by the denominator to find one part, then multiplying by the numerator. Use ratio bars to model the process and solve real-world shopping problems.

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    1 - Getting Started ~4 mins

    Key point

    Illustration for Getting StartedTake a moment to think: what is a smart first step, and what does the bottom number of the fraction tell us to do?

    Here is a question to warm us up. Three quarters of the class of 20 walk to school. How many pupils is that? Hands up if you have a way to start.

    2 - Watch and Notice ~11 mins

    The bars show four fraction problems worked one at a time. Watch how each whole splits into equal parts, and follow the two steps: divide by the bottom, then multiply by the top. The last one turns it around — we know a part and build back to the whole.

    A fraction of an amount

    3 - Try It Together ~11 mins

    Key point

    Each time we split the whole bar into equal parts, find what one part is worth, then take the parts we need.

    Today we work through these together on the ratio bars: 3/4 of 24, then 2/5 of 35, then 5/6 of 48.

    We'll say each first step out loud before anyone touches the board: how many parts, and what is one part worth?

    Work the fractions

    4 - Show the Two Steps in Your Copy ~2 mins

    COPYBOOK MOMENT

    In your maths copy, work each of these problems. For every one, show your two steps clearly: first divide by the bottom to find one part, then multiply by the top to find the answer. Box your answer.

    • 3/4 of 20
    • 2/3 of 18
    • 5/8 of 40

    5 - Class Challenge ~8 mins

    Here are today's challenges: 3/4 of 24 sweets, then 2/3 of a €30 voucher, then 5/6 of 48 minutes. Each one splits the whole into equal parts, then takes the parts the fraction asks for. We finish with a stretch: working backwards from the parts to find the whole.

    Fraction challenge

    Pupil practice
    Module 3 · Fractions, Decimals and Percentages Number
    Lesson 31 · Finding a Fraction of a Quantity
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