Grade DE Round to an appropriate degree of

Grade D/E Round to an appropriate degree of accuracy (e. g. to decimal places or significant figures) If you have any questions regarding these resources or come across any errors, please contact helpful-report@pixl. org. uk

Key Vocabulary Approximation Estimation Decimal Places Significant Figures Degrees of Accuracy

Degree of Accuracy Some questions will ask you to round your answer to an appropriate degree of accuracy. The decision of what you round your answer to will depend on the degree of accuracy required in the problem. Examples If the answer refers to a quantity such as 3. 22 bottles of 7. 83 children then round to a whole number. If the answer refers to money such as £ 24. 7267 then round to 2 decimal places to give £ 24. 73.

Degree of Accuracy For each calculation, give your answers to an appropriate degree of accuracy. (a) 34 x 6. 4 (b) 120. 85 x 0. 78 15. 32 – 4. 09 5. 2 + 2. 9 94. 263 = 8. 393855744 217. 6 = 26. 86419753 11. 23 8. 1 Three of the four values in the question are to one decimal place. So you should round the answer to 26. 9 All four values in the question are to two decimal place. So you should round the answer to 8. 39

Now you try: For each calculation, give your answers to an appropriate degree of accuracy. (a) 8. 3 x 4. 7 (b) 10. 3 + 43. 8 x 8. 9 10. 1 – 3. 3 (c) 64. 83 x 0. 28 51. 83 – 7. 7 (d) 82. 15 + 76 2. 33 x 4. 08 (e) Petrol costs 107. 9 pence per litre. How much in pounds, does 23. 8 litres of petrol cost?

Now you try: For each calculation, give your answers to an appropriate degree of accuracy. (a) 8. 3 x 4. 7 5. 7 (b) 10. 3 + 43. 8 1. 6 3. 8 x 8. 9 10. 1 – 3. 3 (c) 64. 83 x 0. 28 0. 41 51. 83 – 7. 7 (d) 82. 15 + 76 16. 64 2. 33 x 4. 08 (e) Petrol costs 107. 9 pence per litre. How much in pounds, does 23. 8 litres of petrol cost? 1. 079 x 23. 8 = £ 25. 6802 £ 25. 68

Degree of Accuracy Questions such as those involving Pythagoras’ Theorem will expect you to round an answer to an appropriate degree of accuracy. Example, work out the value of the missing length x. 7. 32 m x 5. 68 m

Degree of Accuracy Questions such as those involving Pythagoras’ Theorem will expect you to round an answer to an appropriate degree of accuracy. Example, work out the value of the missing length x. 7. 32 m x 5. 68 m 7. 32² + 5. 68² = x² 85. 8448 = x² x = √ 85. 8448 x = 9. 265246894 Both values in the question are to 2 decimal places. So x should round to 9. 27 m

Reason and Explain A coach can carry 53 passengers. Josh is organising a trip for 276 people. How many coaches does Josh need to hire?

Reason and Explain A coach can carry 53 passengers. Josh is organising a trip for 276 people. How many coaches does Josh need to hire? 276 ÷ 53 = 5. 20754717 This would normally round down to 5 because you can’t have 5. 2 coaches. However, 5 coaches will not be enough because 5 x 53 = 265 So Josh needs to hire 6 coaches.