Roundinng off numbers

MATH 3

1. Read the following numbers. 18, 453 9, 009, 370 570, 045 4, 90,1 067

2. Can you guess the exact number of people in the picture?

3. Rounding-off Numbers

4. Rounding  means making a  number  simpler but keeping its value close to what it was. The result is less accurate, but easier to use.

5. The Rounding Poem Find your number. Look right next door. 4 or less just ignore. 5 or more, add 1 more.

6. Find the place value and circle that digit 2,372 We are rounding to the hundreds place, so we are going to circle the number in the hundreds place.

7. Move to the right , underline the number L ook to the right of the number that is circled. The place value next to the hundreds place is the tens place. Underline the number in the tens place. 2,3 7 2

8. through 4 , C ircle stays the same If the number underlined is 0, 1, 2, 3, 0r 4, leave the number in the circle alone. The number underlined is a 7, so this step does not apply. 2,3 7 2

9. 5 through 9, Add 1 If the number underlined is 5, 6, 7, 8, 0r 9 add 1 to the number in the circle. The number underlined is a 7, so add 1 to the number in the circle. 3 + 1 = 4 2,4 7 2

10. Now flex your muscles like a hero, Digits to the right change to ZERO All the digits to the right of the number in the circle, change to ZERO. The tens place and the ones place are to the RIGHT of the hundreds place. So, the 7 and the 2 both changed to ZERO. 2,400

11. We just rounded 2,372 to the nearest hundred. The nearest hundred is 2,400. 2,300 2,400 2,350 2,372 x 2,372 is closer to 2, 400 rather than 2, 300 .

12. How do we round numbers? To round off a whole number to a specified place value, determine the digit to the right of the place you are rounding off to.

13. If the digit is 5,6,7,8,and 9, round it up or simply add 1 to the digit in the specified place and replace the digits to the right with zeros.

14. If the digit is less than 5 (4,3,2,1,and 0 ) retain the digits in the specified place and replace/change the digits to the right with zero

15. Assignment: Round off to nearest Ten Thousands the ff. numbers. 1) 781 000 2 ) 2 342 670 3 ) 54 671 4 ) 63 421 5 ) 241 584