Topic Check In - 4.01 Approximation and estimation Round the following numbers to the stated accuracy: 1. 6.52 to the nearest whole number. 2. 846.7 to the nearest hundred. 3. 8.0624 to 1 decimal place. 4. 532 236 to 3 significant figures. 5. 0.0472 to 2 significant figures. 6. Given that the formula for area of a circle is A = πr 2 , show that the area of a circle with radius 5 cm is approximately 75 cm2. 7. The exchange rate from GBP (£) to USD ($) is £1 to $1.542. Show that £200 is approximately $300. 8. 3 people had a meal at a restaurant and the total bill was £47.38. They shared the bill equally between them. Explain why they each paid £15.80. 9. The record attendance at Wembley stadium is 89 874. On that day, the average price of a ticket was £55. Estimate the amount of money earned from ticket sales. 10. The flight distance from London to New York is 3462 miles and it takes 6.4 hours. Estimate how far an aeroplane flying from London to New York travels each hour. Extension A ream of paper (500 sheets) is 5.2 cm thick. a) Estimate the thickness of one sheet of paper. b) Estimate the number of sheets that could be stacked from the floor to the ceiling in the classroom. Answers 1. 7 2. 800 3. 8.1 4. 532 000 5. 0.047 6. π = 3.1415… is approximately 3 so 3 × 25 = 75 7. 1.542 is approximately 1.5 so 200 × 1.5 = 300 8. 47.38 ÷ 3 = 15.793333... but you must round up to ensure the bill is paid 9. Approximately 90 000 × 60 = 5 400 000 oe therefore approximately £5 million 10. Approximately 3000 ÷ 6 = 500 miles Extension a) 5 ÷ 500 = 0.01 cm (or 0.1 mm) b) Dependent upon classroom, but approximately 10 000 sheets for every metre high We’d like to know your view on the resources we produce. By clicking on the ‘Like’ or ‘Dislike’ button you can help us to ensure that our resources work for you. When the email template pops up please add additional comments if you wish and then just click ‘Send’. Thank you. 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Thumbs up and down icons: alexwhite/Shutterstock.com Please get in touch if you want to discuss the accessibility of resources we offer to support delivery of our qualifications: [email protected] Assessment Objective Qu. Topic R A G Assessment Objective Qu. Topic AO1 1 Round to nearest whole number. AO1 1 Round to nearest whole number. AO1 2 Round to nearest hundred. AO1 2 Round to nearest hundred. AO1 3 Round to decimal places. AO1 3 Round to decimal places. AO1 4 Round to significant figures. AO1 4 Round to significant figures. AO1 5 Round decimals to significant figures. AO1 5 Round decimals to significant figures. AO2 6 Estimate a calculation involving pi. AO2 6 Estimate a calculation involving pi. AO2 7 Use an approximate value to estimate an answer. AO2 7 Use an approximate value to estimate an answer. AO2 8 Round values appropriately in context. AO2 8 Round values appropriately in context. AO3 9 Use appropriate approximations to estimate an answer. AO3 9 Use appropriate approximations to estimate an answer. AO3 10 Use appropriate approximations to estimate an answer. AO3 10 Use appropriate approximations to estimate an answer. Assessment Qu. Assessment Qu. Objective Topic R A G Objective Topic AO1 1 Round to nearest whole number. AO1 1 Round to nearest whole number. AO1 2 Round to nearest hundred. AO1 2 Round to nearest hundred. AO1 3 Round to decimal places. AO1 3 Round to decimal places. AO1 4 Round to significant figures. AO1 4 Round to significant figures. AO1 5 Round decimals to significant figures. AO1 5 Round decimals to significant figures. AO2 6 Estimate a calculation involving pi. AO2 6 Estimate a calculation involving pi. AO2 7 Use an approximate value to estimate an answer. AO2 7 Use an approximate value to estimate an answer. AO2 8 Round values appropriately in context. AO2 8 Round values appropriately in context. AO3 9 Use appropriate approximations to estimate an answer. AO3 9 Use appropriate approximations to estimate an answer. AO3 10 Use appropriate approximations to estimate an answer. AO3 10 Use appropriate approximations to estimate an answer. R A G R A G

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