PAss Functional Skills

Tree diagrams

Tree diagrams for GCSE Health and Social Care AQA Foundation: what it means, how to set the working out, and the questions it is asked in.
  • GCSE
  • AQA
  • Health and Social Care
  • Foundation
  • Spec S19
  • 10 min read
  • 8 revision boxes

Introduction

2 boxes
3 min read

What is tree diagrams?

Listen to this box

Transcript

A short spoken summary of tree diagrams and where it is used.

A spoken walk-through of tree diagrams before you read the notes.
The examiner marks the working, so a correct answer with no method still drops marks.
The layout below is the one the mark scheme expects.

Diagram showing tree diagrams laid out step by step

The same idea drawn out, so the method is visible.
Worth knowing: 34×25\frac{3}{4} \times \frac{2}{5}.
5 rows

The tree diagrams reference table

This idea appears again in the higher-mark questions, so it is worth over-learning.
Worth knowing: x2+5x+6=0x^2 + 5x + 6 = 0.
Term
Meaning
Example
Row 1 column 1
Row 1 column 2
49=7\sqrt{49} = 7
Row 2 column 1
Row 2 column 2
a2+b2=c2a^2 + b^2 = c^2
Row 3 column 1
Row 3 column 2
a2+b2=c2a^2 + b^2 = c^2
Row 4 column 1
Row 4 column 2
34×25\frac{3}{4} \times \frac{2}{5}

Learning

4 boxes
5 steps

How to work with tree diagrams

Sketch the shape even when the question does not ask for one — it makes the next step obvious.
  1. Read the question and write down what is being asked for.
  2. Set out the working for tree diagrams in the order the method gives.
  3. Substitute the values and simplify.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: a2+b2=c2a^2 + b^2 = c^2.
Answer: 34×25\frac{3}{4} \times \frac{2}{5}
3 rules

Key facts: Tree diagrams

Practise the routine version until it is automatic, then move to the multi-step questions.
The layout below is the one the mark scheme expects.

Diagram showing tree diagrams laid out step by step

The same idea drawn out, so the method is visible.
Worth knowing: ×10\times 10 moves every digit one column left.

  • Rule 1

    How tree diagrams behaves in the 1st of the cases the specification names.
    ×10\times 10 moves every digit one column left

  • Rule 2

    How tree diagrams behaves in the 2nd of the cases the specification names.
    34×25\frac{3}{4} \times \frac{2}{5}

  • Rule 3

    How tree diagrams behaves in the 3rd of the cases the specification names.
    34×25\frac{3}{4} \times \frac{2}{5}
5 steps

How to work with tree diagrams

The examiner marks the working, so a correct answer with no method still drops marks.
  1. Read the question and write down what is being asked for.
  2. Set out the working for tree diagrams in the order the method gives.
  3. Substitute the values and simplify.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: ≈160\approx 160.
Answer: ×10\times 10 moves every digit one column left
2 rules

Key facts: Tree diagrams

This idea appears again in the higher-mark questions, so it is worth over-learning.

  • Rule 1

    How tree diagrams behaves in the 1st of the cases the specification names.
    34×25\frac{3}{4} \times \frac{2}{5}

  • Rule 2

    How tree diagrams behaves in the 2nd of the cases the specification names.
    a2+b2=c2a^2 + b^2 = c^2

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Examples

2 boxes
2 marks · worked

Worked example: tree diagrams

The specification wording is precise here, and the mark scheme follows that wording exactly.
The layout below is the one the mark scheme expects.

Diagram showing tree diagrams laid out step by step

The same idea drawn out, so the method is visible.
4 marks · worked

Practice question 8: a2+b2=c2a^2 + b^2 = c^2

Read the units in the question before you start; a converted unit is the most common slip.

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Common questions

How many marks is tree diagrams usually worth?
Between one and four, depending on how many steps the question asks for.
Is this on the GCSE Health and Social Care AQA Foundation paper?
Yes — it sits in the Markets and demand strand.