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rounding-value for grade 7 students_.ppt
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- 2. © T Madas Sometimeswe have to round numbers What does rounding mean? Can you think of some examples?
- 3. © T Madas 40 40 Roundingto the nearest 10 The rounded number must have a zero at the end Round 37 to the nearest 10 30 37
- 4. © T Madas Roundingto the nearest 10 The rounded number must have a zero at the end Round 154 to the nearest 10 160 150 154 150
- 5. © T Madas Roundingto the nearest 10 Round 125 to the nearest 10 130 120 125 130 When our number lies halfway between “tens”, we have agreed to round the number up.
- 6. © T Madas Roundingto the nearest 10 Numbers ending in 1, 2, 3 and 4 get rounded down Numbers ending in 5, 6, 7 , 8 and 9 get rounded up Examples: 27 30 94 90 146 150 305 310 68 70 132 130 565 570 481 480
- 7. © T Madas 800 800 Roundingto the nearest 100 The rounded number must have 2 zeros at the end Round 764 to the nearest 100 700 764
- 8. © T Madas 1200 1200 Therounded number must have 2 zeros at the end Round 1235 to the nearest 100 1300 1235 Rounding to the nearest 100
- 9. © T Madas 900 900 Round850 to the nearest 100 800 850 When our number lies halfway between “hundreds”, we have agreed to round the number up. Rounding to the nearest 100
- 10. © T Madas Numbersending in 0s, 10s, 20s, 30s and 40s get rounded down Numbers ending in 50s, 60s, 70s , 80s and 90s get rounded up Examples: 237 200 874 900 536 500 350 400 1168 1200 2032 2000 5750 5800 40081 40100 Rounding to the nearest 100
- 11. © T Madas 8000 8000 Roundingto the nearest 1000 The rounded number must have 3 zeros at the end Round 7761 to the nearest 1000 7000 7761
- 12. © T Madas 8000 8000 Therounded number must have 3 zeros at the end Round 8339 to the nearest 1000 9000 8339 Rounding to the nearest 1000
- 13. © T Madas 7000 7000 Round6500 to the nearest 1000 6000 6500 When our number lies halfway between “thousands”, we have agreed to round the number up. Rounding to the nearest 1000
- 14. © T Madas Numbersending in 00s, 100s, 200s, 300s and 400s get rounded down Numbers ending in 500s, 600s, 700s , 800s and 900s get rounded up Examples: 2837 3000 4874 5000 5376 5000 7500 8000 1868 2000 2499 2000 29780 30000 45681 46000 Rounding to the nearest 1000
- 15. © T Madas PracticeRounding to the nearest…
- 16. © T Madas Roundthese numbers to the nearest… 48 87 184 145 1563 3217 2005 50 90 180 150 1560 3220 2010 …10 209 2867 3467 1095 1550 45678 61981 200 2900 3500 1100 1600 45700 62000 …100 3456 5349 89231 37849 32489 49838 71974 3000 5000 89000 38000 32000 50000 72000 …1000 …whole number 2.7 4.2 10.4 3 4 10 27.9 7.67 33.37 28 8 33 31.436 764.92 0.86 31 765 1
- 17. © T Madas Roundthese numbers to the nearest… 78 67 181 125 1343 3787 1998 80 70 180 130 1340 3790 2000 …10 279 2557 23107 16915 1850 49805 61041 300 2600 23100 16900 1900 49800 61000 …100 76532 64543 37859 90832 98114 89575 70456 77000 65000 38000 91000 98000 90000 70000 …1000 …whole number 2.8 8.2 11.4 3 8 11 37.9 7.17 39.67 38 7 40 37.685 344.02 0.81 38 344 1
- 18. © T Madas QuickTest on Rounding to the nearest…
- 19. © T Madas Roundthese numbers to the nearest… 48 87 184 145 1563 3217 2005 50 90 180 150 1560 3220 2010 …10 209 2867 3467 1095 1550 45678 61981 200 2900 3500 1100 1600 45700 62000 …100 3456 5349 89231 37849 32489 49838 71974 3000 5000 89000 38000 32000 50000 72000 …1000 …whole number 2.7 4.2 10.4 3 4 10 27.9 7.67 33.37 28 8 33 31.436 764.92 0.86 31 765 1
- 20. © T Madas Roundthese numbers to the nearest… 78 67 181 125 1343 3787 1998 80 70 180 130 1340 3790 2000 …10 279 2557 23107 16915 1850 49805 61041 300 2600 23100 16900 1900 49800 61000 …100 76532 64543 37859 90832 98114 89575 70456 77000 65000 38000 91000 98000 90000 70000 …1000 …whole number 2.8 8.2 11.4 3 8 11 37.9 7.17 39.67 38 7 40 37.685 344.02 0.81 38 344 1
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- 22. © T Madas Welook at the 1st decimal place • If it is 0, 1, 2, 3 or 4 we just throw all the decimal digits away • If it is 5, 6, 7, 8 or 9 we throw all the decimal digits away and we increase the units by 1 Rounding decimals… to the nearest whole number Examples: 23.7 24 8.94 9 53.6 54 3.52 4 1.768 2 20.32 20 5.8757 6 40.071 40
- 23. © T Madas Welook at the 2nd decimal place • If it is 0, 1, 2, 3 or 4 we just throw the 2nd , the 3rd , the 4th … decimal digits away • If it is 5, 6, 7, 8 or 9 we throw the 2nd , the 3rd , the 4th … decimal digits away and we increase the 1st decimal digit by 1 Rounding decimals… to one decimal place Examples: 3.734 3.7 8.294 8.3 9.16 9.2 6.52 6.5 5.728 5.7 41.32 41.3 5.8757 5.9 40.071 40.1
- 24. © T Madas Welook at the 3rd decimal place • If it is 0, 1, 2, 3 or 4 we just throw the 3rd , the 4th , the 5th … decimal digits away • If it is 5, 6, 7, 8 or 9 we throw, the 3rd , the 4th , the 5th … decimal digits away and we increase the 2nd decimal digit by 1 Rounding decimals… to two decimal places Examples: 3.7342 3.73 5.2863 5.29 0.1605 0.16 2.5782 2.58 5.7028 5.70 4.3592 4.36 5.8957 5.90 4.9971 5.00
- 25. © T Madas PracticeRounding to Decimal Places
- 26. © T Madas 0.49978 8.5328 3.5004 4.089623 6.40078 5.36581 0.10704 1.48173 2.2258 9.2341 Roundthe following numbers to 1 decimal places 0.49878 7.3058 2.585423 0.46878 2.3553 9.48973 1.3173 8.75438 4.6751 1.56437 6.39745 5.471 3.117 1.867 1.9 5.5 0.43456 6.4 5.245567 0.9034 1.6 4.7 8.8 2.724 1.32 9.49 4.1424 2.36 0.47 3.5024 2.59 7.31 0.50 2.226 1.482 5.366 6.401 4.090 8.533 0.500 2 3
- 27. © T Madas QuickTest on Number Rounding to Decimal Places
- 28. © T Madas 5.36581 0.10704 1.48173 2.2258 9.2341 Roundthe following numbers to decimal places 2.3553 9.48973 1.3173 6.39745 5.471 3.117 1.867 1.9 5.5 0.43456 6.4 2.724 1.32 9.49 4.1424 2.36 2.226 1.482 5.366 1 d.p. 2 d.p. 3 d.p.
- 29. © T Madas Roundthe following numbers to decimal places 1 d.p. 2 d.p. 3 d.p. 0.49978 8.5328 3.5004 4.089623 6.40078 0.49878 7.3058 2.585423 0.46878 8.75438 4.6751 1.56437 5.245567 0.9034 1.6 4.7 8.8 0.47 3.5024 2.59 7.31 0.50 6.401 4.090 8.533 0.500
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