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Percentage Error Worksheet

GCSE / A LevelHard15 questions

Free to print and use in your classroom. No sign-up required.

Formula

Percentage Error = (|Approximate − Exact| ÷ Exact) × 100

The vertical bars mean ‘absolute value’ — always use the positive difference between the two values.

Calculate the percentage error using: Percentage Error = (|Approximate - Exact| / Exact) x 100. Give answers to 2 decimal places where necessary.

  1. Q1. A student estimates a length as 80 cm. The actual length is 85 cm. Calculate the percentage error.

  2. Q2. A pupil predicts 120 cars will pass in an hour. Actually 100 pass. Calculate the percentage error.

  3. Q3. A student estimates the mass of an object as 45 g. The actual mass is 50 g. Find the percentage error.

  4. Q4. A measurement of 9.5 cm is taken. The true value is 10 cm. Find the percentage error.

  5. Q5. A weather forecast predicts 250 mm of rain but only 200 mm falls. Find the percentage error.

  6. Q6. A pupil predicts 75 people will attend an event. Actually 80 people attend. Find the percentage error.

  7. Q7. A scientist estimates the volume as 36 ml. The exact volume is 40 ml. Find the percentage error.

  8. Q8. A pupil measures a line as 11.4 cm. The actual length is 12 cm. Find the percentage error.

  9. Q9. A student estimates the cost of a holiday as £180. It actually costs £200. Find the percentage error.

  10. Q10. A thermometer reads 47 degrees C. The actual temperature is 50 degrees C. Find the percentage error.

  11. Q11. A budget estimate is £350. The actual cost is £400. Find the percentage error.

  12. Q12. A student weighs a rock as 2.4 kg. The true mass is 2.5 kg. Find the percentage error.

  13. Q13. An estimate of 63 ml is made for a liquid. The exact amount is 70 ml. Find the percentage error.

  14. Q14. A student predicts a score of 95. The actual score is 100. Find the percentage error.

  15. Q15. A student measures a shadow as 28 cm. The true length is 32 cm. Find the percentage error.

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Worked Answers

  1. Q1. |80 − 85| / 85 × 100 = 5 / 85 × 100 = 5.88%
  2. Q2. |120 − 100| / 100 × 100 = 20 / 100 × 100 = 20%
  3. Q3. |45 − 50| / 50 × 100 = 5 / 50 × 100 = 10%
  4. Q4. |9.5 − 10| / 10 × 100 = 0.5 / 10 × 100 = 5%
  5. Q5. |250 − 200| / 200 × 100 = 50 / 200 × 100 = 25%
  6. Q6. |75 − 80| / 80 × 100 = 5 / 80 × 100 = 6.25%
  7. Q7. |36 − 40| / 40 × 100 = 4 / 40 × 100 = 10%
  8. Q8. |11.4 − 12| / 12 × 100 = 0.6 / 12 × 100 = 5%
  9. Q9. |180 − 200| / 200 × 100 = 20 / 200 × 100 = 10%
  10. Q10. |47 − 50| / 50 × 100 = 3 / 50 × 100 = 6%
  11. Q11. |350 − 400| / 400 × 100 = 50 / 400 × 100 = 12.5%
  12. Q12. |2.4 − 2.5| / 2.5 × 100 = 0.1 / 2.5 × 100 = 4%
  13. Q13. |63 − 70| / 70 × 100 = 7 / 70 × 100 = 10%
  14. Q14. |95 − 100| / 100 × 100 = 5 / 100 × 100 = 5%
  15. Q15. |28 − 32| / 32 × 100 = 4 / 32 × 100 = 12.5%

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