Functional Skills Maths: Graphs

Read line graphs and understand trends

What is a Line Graph?

  • A line graph shows how something changes over time.
  • The horizontal axis (x) usually shows time.
  • The vertical axis (y) shows the amount.
  • A line going up means values are increasing.
  • A line going down means values are decreasing.

Reading a Line Graph

  • Find the time point you want on the x-axis.
  • Move straight up to the line.
  • Then move across to the y-axis to read the value.

Understanding Trends

  • A rising line shows growth or increase.
  • A falling line shows decline or decrease.
  • A flat line shows no change.
  • A zig-zag line shows values going up and down.

Worked Examples

Example 1: Reading a change in temperature

  1. Temperature at 6 AM: 10°C.
  2. Temperature at 2 PM: 20°C.
  3. Change: 20 − 10 = 10°C increase.

Example 2: Identifying a trend

  1. Jan sales: 100. Feb: 120. Mar: 110.
  2. Sales rose from Jan to Feb (up by 20).
  3. Sales fell from Feb to Mar (down by 10).

Practice Questions

  • A line goes from 4 to 8 over 2 hours. How much did it increase?
    Hint: 8 − 4.
    Answer: 4
  • Value at 9 AM: 15. At 11 AM: 25. How much did it change?
    Hint: 25 − 15.
    Answer: Increased by 10
  • Start: 50. End after 3 hours: 20. Did it increase or decrease?
    Hint: Is 20 more or less than 50?
    Answer: Decrease — fell by 30
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