1. Rounding and Approximation

2. Methods of Rounding Decimal Places Identify the digit of the decimal place required  Look at the next digit to the right  If this digit is 5 or more round up the required decimal place

3. Examples Ex Round 5.346 to 2 decimal places 2 nd decimal place is the 4 i.e 2 places after the decimal point The next number to the right is a 6 So round up 5.346 becomes 5.35 to 2 decimal places

4. Examples Ex Round 5.346 to 1 decimal place 1st decimal place is the 3 i.e 1 place after the decimal point The next number to the right is a 4 So Don`t round up 5.346 becomes 5.3 to 1 decimal places

5. Questions 1.6.182 to 1d.p 2. 72.457 to 2d.p 3. 35.21632 to 3d.p 4. 35.21632 to 2d.p 5. 6.983 to 1d.p 6.2 72.46 35.216 35.22 7.0

6. Methods of Rounding Significant Figures Identify the digit of the significant figure required. This means start counting from the first non zero digit  Look at the next digit to the right  If this digit is 5 or more round up the required significant figure

7. Examples Ex Round 5.346 to 2 significant figures 2 nd significant figure from the start is the 3 The next number to the right is a 4 So Don`t round up 5.346 becomes 5.3 to 2 significant figures

8. Examples Ex Round 5.346 to 3 significant figures 3rd significant figure is the 4 i.e 3 places from the start The next number to the right is a 6 So round up 5.346 becomes 5.35 to 3 significant figures

9. Examples Ex Round 25.346 to 1 significant figures 1st significant figure is the 2 i.e 1 place from the start The next number to the right is a 5 So round up but remember the answer must be 30 not 3 as the original number is closer to 30 than 20 25.346 becomes 30 to 1 significant figures

10. Questions 1.6.182 to 1s.f 2. 72.657 to 2s.f 3. 35.21632 to 3s.f 4. 35.21632 to 4s.f 5. 16.983 to 1s.f 6 73 35.2 35.22 20

11. Notes

12. Methods of Rounding Decimal Places Identify the digit of the decimal place required Look at the next digit to the right If this digit is 5 or more round up the required decimal place Ex Round 5.346 to 2 decimal places 2 nd decimal place is the 4 i.e 2 places after the decimal point The next number to the right is a 6 So round up 5.346 becomes 5.35 to 2 decimal places

13. Significant Figures Identify the digit of the significant figure required. This means start counting from the first non zero digit Look at the next digit to the right If this digit is 5 or more round up the required significant figure Ex Round 5.346 to 3 significant figures 3 rd significant figure from the start is the 4 The next number to the right is a 6 So round up 5.346 becomes 5.35 to 3 significant figures