1. Rounding Numbers. 6 7 8 6.3 7.2 7.8 2035 = 2040 8985 = 9000 6.89 = 6.9 67 890 = 68 000

2. Rounded Numbers All Around You. Here are some examples of rounded numbers which could appear in newspaper headlines: 30 000 Watch Scotland Win Again. Man Leaves £2 Million To Charity. 500 000 March In War Protest. ©Microsoft Word clipart

3. Rounding To The Nearest Whole Number. Consider the number : 6.7 It is our task to decide if the number is closer to : 6 or 7 Look at the number line below: 6 7 8 Mark the number 6.5 6.5 Mark the number 6.7 6.7 Is 6.7 closer to 6 or 7 ? 6.7 = 7 (to the nearest whole number) 6.5 is the midpoint between 6 and 7. Is 6.7 above or below 6.5 ?Above

4. Further Example. Round the following to the nearest whole number: (1) 24.3 24 25 26 What is the midpoint between 24 and 25 ? 24.5 Is 24.3 above or below 24.5 ? 24.3 Below. 24.3 = 24 (To the nearest whole number).

5. What Goes In The Box ? Round the following to the nearest whole number: (1) 4.8 (2) 7.4 NB: always round 0.5 up. Ie 12.5 = 13 (to the nearest whole number). (3) 44.6 (4) 87.5 (5) 56.3 (6) 287.6 (7) 9.8 (8) 49.6 (9) 99.7 (10) 399.5 5 7 44 88 56 288 10 50 100 400

6. Rounding To 1 Decimal Place. Round 4.67 to one decimal place (1d.p). 4.64.7 Mark 4.67 on the number line. 4.67 Is 4.67 closer to 4.6 or 4.7 ?4.7 4.67 = 4.7 (to 1d.p) What number is the arrow pointing at ? 4.65

7. Round 19.53 to 1 d.p. 19.519.6 Mark 19.53 on the number line. 19.53 Is 19.53 closer to 19.5 or 19.6 ?19.5 19.53 = 19.5 (to 1d.p) What number is the arrow pointing at ? 19.55

8. What Goes In The Box ? 2 Round the following to 1 decimal place. (1) 34.67 = (2) 17.72 = (3) 24.75 = (4) 41.92 = (5) 56.95 = (6) 39.97 = (7) 99.96 = (8) 999.95 = 34.7 17.7 24.8 41.9 60 40 100 1000

9. Rounding To 2 Decimal Places. In order to make this a faster process we will take a different approach: Round 45.678 to 2 decimal places ( 2 d.p). What number is the second after the point ? 7 Is the number after the seven greater or smaller than 5 ? 8 is greater than 5 (or 8 > 5) Rule If the number is greater than or equal to 5 then round up. Now round 45.678 to 2 d.p 45.678 = 45.68 (to 2 d.p)

10. Round 23.482 to 2 decimal places ( 2 d.p). What number is the second after the point ? 8 Is the number after the eight greater or smaller than 5 ? 2 is less than 5 (or 2 < 5) Rule If the number is greater than or equal to 5 then round up. Now round 23.482 to 2 d.p 23.482 = 23.48 (to 2 d.p)

11. What Goes In The Box ? 3 Round the numbers below to 2 decimal places. (1) 45.783 = (2) 37.677 = (3) 6.4589 = (4) 0.4291 = (5) 36.995 = (6) 99.992 = (7) 0.097 = (8) 999.9958 = 45.78 37.68 6.46 0.43 37 99.99 0.1 1000

12. Rounding To The Nearest 10,100,1000 etc. Round 467 to the nearest ten. Which number is the tens number ? 6 Is the number after the 6 greater or smaller than 5 ? 7 > 5 Rule If the number is greater than or equal to 5 then round up. Now round 467 to the nearest ten. 467= 470 (to the nearest ten). 460470 467

13. Round 23 438 to the nearest hundred. Which number is the hundreds number ? 4 Is the number after the 4 greater or smaller than 5 ? 3 < 5 Rule If the number is greater than or equal to 5 then round up. Now round 23 438 to the nearest hundred. 23 438= 23 400 (to the nearest hundred). 23 40023 500 23 438

14. What Goes In The Box ? 4 Round the numbers below to the required unit: (1) 34 567 to the nearest ten = (2) 47 943 to the nearest hundred = (3) 356 518 to the nearest thousand = (4) 356 218 to the nearest ten thousand = 34 570 47 900 357 000 360 000