1. Rounding Whole Numbers
September 8, 2009

2. Steps for rounding
Find the rounding place value. Example: Round to the nearest ten-thousand.
23,584

3. Look to the digit to the right of this place value
Look to the digit to the right of this place value. Which number is to the right of the ten-thousand place value?
23,584

4. If the digit is 5 or greater than add 1 to the rounding digit
If the digit is 5 or greater than add 1 to the rounding digit. If the digit is less than 5, leave the rounding digit alone. Which one will I do here?
23,584

5. Change all digits to the right of the rounding number to zeros.

6. Round each number to the underlined place value.
Practice
Round each number to the underlined place value.
3,101,922
45,699,825
895,774
6,498,555

7. Answers
3,101, ,101,900
45,699, ,700,000
895, ,770
6,498, ,499,000

8. More practice
Write three numbers that would round to 72,000,000 when rounded to the nearest million.

9. Answers vary
72,000,000
If you want to keep the number 72 million he place value to the right of the 2, which is RED can only be 0,1,2,3,4. The of the numbers to the right of the hundred thousand place value can be anything.
Examples: 72,199,999; 72,258,698; 72,444,444
71,000,000
If you to round 71 million up to 72 million than the number to the right of the 1, which is in BLUE can only be 5,6,7,8,9. The of the numbers to the right of hundred thousand place value can be anything.
Examples: 71,999,999; 71,555,555; 71,795,846

10. Mixed Review Order the following numbers from least to greatest?
9,781; 9,178; 917; 9,187; 8,971
Which of the following is not true?
13=1x1x1 b) 33=27 c) Three squared is 9.
d) 52=5x2

11. Homework
Pg. 4 in Math Workbook