1. ESTIMATION AND ROUNDING

2. Rounding two-digit numbers
RULES FOR ROUNDING
Two-digit number will be rounded to the nearest ten.
Underline the number in the place value you will round.
2. Look at the number to the right of the underlined number.
If the number to the right is 0, 1, 2, 3, or 4, then the underlined number stays the same. 26 3
If the number to the right is 5, 6, 7, 8, or 9, then the underlined number needs to go up one more number.
So we can say that th closer to 30 than to 20.
Every number to the right of the underlined number becomes a zero.

3. Rounding three-digit numbers
RULES FOR ROUNDING
Three-digit number will be rounded to the nearest hundred.
Underline the number in the place value you will round.
2. Look at the number to the right of the underlined number.
If the number to the right is 0, 1, 2, 3, or 4, then the underlined number stays the same.
520 5
If the number to the right is 5, 6, 7, 8, or 9, then the underlined number needs to go up one more number.
So we can say that the number 520 is closer to 500 than to 600.
Every number to the right of the underlined number becomes a zero.

4. 26 is closer to 30 than to 20. 26 20 30
520 is closer to 500 than to 600.
500
520
600

5. 10 + 10 ------- 12 + 8 ------- 20 Estimating sums
First, round all the numbers using the RULES FOR ROUNDING .Then, perform the operations. 20

6. Estimating differences
First, round all the numbers using the RULES FOR ROUNDING. Then, perform the operations.
200

7. Now you practice. Round these numbers.25 78 36
158
689
324 30 80 40
200
700
300

8. Rounding Whole Numbers Through Millions
By Mr. Bales

9. Objective
You will be able to round whole numbers through the millions to the nearest 10, 100, 1,000, 10,000, or 100,000

10. Problem
Each year immigrants from around the world come to the United States. In 2003, California schools welcomed 175,090 immigrant students.
What is 175,090 rounded to the nearest thousand?

11. Let’s Hear a Song About Rounding!!
By Mr. Bales
Let's Watch Mr. Parsons!!

12. How To Round Let’s look at this number 175,090.
First, underline the place value that you want to round.
Then, look at the digit to the right. If the digit is 4 or less, the digit in the rounding place stays the same.
If the digit to the right is 5 or more. The digit in the rounding place increases by one.
Last, change all the digits to the right of the rounding place to zero.

13. Game Time!! Round to the nearest hundred 71,105 654,354 678,947
Round to the nearest ten thousand
1,256,876
23,786,983
Round to the nearest hundred thousand
234,654,899
3,853,216
Round the nearest million
34,652,985
976,634,321

14. Your turn!

15. Your turn!

16. Estimate each product, addition and subtraction.
1. 62 X X X 302