Chapter 3 Approximation Estimation Learning Outcomes Round to

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Chapter 3 Approximation & Estimation

Chapter 3 Approximation & Estimation

Learning Outcomes Round to nearest 10, 1000 Round in practical problems Round to a

Learning Outcomes Round to nearest 10, 1000 Round in practical problems Round to a specified number of decimal places Round to a specified number of significant figures Choosing a degree of accuracy for the answer that suits the question Estimating calculations

Rounding to nearest 10, 100, … n If 5 or above round up n

Rounding to nearest 10, 100, … n If 5 or above round up n If below 5 leave alone Number 7834 8323 20911 90892 9999 Nearest 1000

Practical Problems n Remember sensible!!!! to think if your answer is n Example A

Practical Problems n Remember sensible!!!! to think if your answer is n Example A year group are going on a trip to Paris. There are 242 students going. Each bus holds 55 passengers. How many buses are needed?

Rounding Decimals n Start counting after the decimal place Number 1 dp 2. 7849

Rounding Decimals n Start counting after the decimal place Number 1 dp 2. 7849 2. 34535 0. 0234 0. 99999 2 dp 3 dp 4 dp

Significant Figures n Start counting at the 1 st non-zero digit Number 1 sf

Significant Figures n Start counting at the 1 st non-zero digit Number 1 sf 2. 7849 234. 535 0. 0234 99. 999 2 sf 3 sf 4 sf

Choosing a Degree of Accuracy n Use common sense!!! n If answer is in

Choosing a Degree of Accuracy n Use common sense!!! n If answer is in metres use 2 dp n If a question is given to 1 dp the answer should be given to 1 dp

Estimation n When estimating a calculation use 1 significant figure or round to numbers

Estimation n When estimating a calculation use 1 significant figure or round to numbers that give even answers n Examples 1) Estimate 432 × 29 2) Estimate (49. 7 + 10. 6) ÷ (9. 69 × 3. 04) 3) Estimate 78. 9 ÷ (0. 037 × 5. 2)