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3. If you read in the Saturday sports section of the paper that the attendance at a football match was exactly 43,786 and a friend asked you about the attendance at school on Monday, you would probably say about 44,000. In this case you are giving an approximate answer to 2 S.f. Significant Figures It is often necessary/convenient/sensible to give approximations to real life situations or as answers to certain calculations.

4. 4. 3 3 2 5 Significant Figures (Rounding) Numbers can be rounded to 1,2, 3 or more significant figures. We count the number of figures from the first non-zero digit. Rounding to 1 s.f 5 or bigger ? 4 5. 7 4 2 5 5 or bigger ? 6 0. 0 4 2 5 5 or bigger ? 0.04 NoYes No First non-zero digit.

5. Rounding to 1 s.f 0. 0 7 6 5 or bigger ? 0.08 0. 0 0 1 5 5 or bigger ? 0.002 Yes First non-zero digit. Significant Figures (Rounding)

6. 1. 4 7 2 9 5 or bigger ? 1.5 0. 0 5 3 5 5 or bigger ? 0.054 Yes First non-zero digit. Significant Figures (Rounding) Rounding to 2 s.f

7. 6. 0 7 2 9 5 or bigger ? 6.1 0. 0 0 0 5 6 3 5 or bigger ? 0.00056 Yes No First non-zero digit. Significant Figures (Rounding) Rounding to 2 s.f

8. 2. 0 7 5 9 5 or bigger ? 2.08 0. 0 2 0 4 6 3 5 or bigger ? 0.0205 Yes First non-zero digit. Significant Figures (Rounding) Rounding to 3 s.f

9. 2. 0 7 5 1 5 or bigger ? 2.075 0. 0 1 0 2 3 8 3 5 or bigger ? 0.01024 No Yes First non-zero digit. Significant Figures (Rounding) Rounding to 4 s.f

10. Significant Figures (Rounding) When we approximate whole numbers we may need to insert zeros as required in order to maintain the size of the number. Rounding whole numbers to 1 s.f 1 4 7 2 5 or bigger ? 1 000 No 2 2 7 2 8 5 or bigger ? 20 000 No 4 8 8 1 3 5 5 or bigger ? 500 000 Yes

11. Significant Figures (Rounding) When we approximate whole numbers we may need to insert zeros as required in order to maintain the size of the number Rounding whole numbers to 1 s.f 2 4 1 5 or bigger ? 200 No 5 8 7 5 or bigger ? 600 Yes 7 5 5 or bigger ? 80 Yes

12. Significant Figures (Rounding) When we approximate whole numbers we may need to insert zeros as required in order to maintain the size of the number Rounding whole numbers to 2 s.f 1 4 7 2 5 or bigger ? 1 500 Yes 4 2 7 2 8 5 or bigger ? 43 000 Yes 2 0 4 4 7 8 5 or bigger ? 200 000 No

13. Significant Figures (Rounding) When we approximate whole numbers we may need to insert zeros as required in order to maintain the size of the number Rounding whole numbers to 2 s.f 2 4 3 5 or bigger ? 240 No 2 8 7 5 or bigger ? 290 Yes 7 5 6 5 or bigger ? 760 Yes

14. Significant Figures (Rounding) When we approximate whole numbers we may need to insert zeros as required in order to maintain the size of the number Rounding whole numbers to 3 s.f 5 4 7 2 5 or bigger ? 5 470 No 8 3 7 9 8 5 or bigger ? 83 800 Yes 9 7 4 9 7 8 5 or bigger ? 975 000 Yes

15. Significant Figures (Rounding) When we approximate whole numbers we may need to insert zeros as required in order to maintain the size of the number Rounding whole numbers to 4 s.f 3 4 7 2 1 5 or bigger ? 34 720 No 1 3 7 9 8 5 or bigger ? 13 800 Yes 6 2 4 7 7 8 5 or bigger ? 624 800 Yes

16. The following number could be the population of a country at a particular instant in time.Write this number to 1, 2, 3, 4, 5, 6 and 7 significant figures. 56 345 678 60 000 000 56 000 00056 300 000 56 350 00056 346 000 56 345 700 56 345 680