1. Front End & Rounding Gwendolyn Best Suffolk Public Schools
Estimation Strategies

2. Estimation The next few slides will help you test your
estimation skills.

3. Can I buy three for $100? 45

4. Can I buy three for $100?
$23

5. Can I buy 5 for $50?
$11.87
The basketball would have to cost ______ or less for me to purchase five of them for $50.

6. Can I buy three for $20?
CHECKERS
$4.95

7. Rounding to the highest Place Value
Round each number to its highest possible place value. Some numbers will be rounded to ten- thousands, thousands, hundreds, or tens.

8. What is the highest place value of each number?,
What is the highest place value of each number?
375
Hundreds 26
Tens
1,427
Thousands
216

9. Round to the highest place.
375
Hundreds
400 26
Tens 30
1,427
Thousands
1,000
216
200

10. After you round, add the numbers!
400
  30
1000
+ 200
1630

11. Round each number to the highest place value?
8857
  4758
7045
8857
  4758
7045
+ 2110
9000
5000
7000

12. Estimate to choose the most reasonable answer.
Between 11,000 and 15,000
Between 16,000 and 20,000
Between 20,000 and 25,000
Between 28,000 and 33,000
9000
  5000
7000
+2000

13. Round each number to the highest place value?
247
6542
489
247
6542
489
200
7000
500

14. 200 7000 500 + 90 A little less than 7,000 A little less than 8,000
A little more than 8,000
A little more than 10,000
200
7000
500

15. Round each number to the highest place value?
5028
6732
1285
5000
5028
6732
1285
7000
1000

16. Front End Estimation
Estimation Strategy

17. FRONT END
The name of this strategy gives you a clue about how it is used.
The word FRONT should remind you that you are only concerned with the front portion of the number.
Many people think this strategy is easier than rounding to the highest place value.

18. Draw a line through your list of numbers so that you have at least one digit from each addend in front of (before) the line.
Change all numbers after the line to zeros.
4,329
748
2,398
4,32 0
74 0
2,39 0
All numbers before the line stay the same.

19. Where will we place the line if using front end estimation?,
Where will we place the line if using front end estimation?
375
37 0 26
2 0
1,427
1,42 0
216
21 0

20. Use the front end estimation strategy.
8857
  4758
7045
8857
  4758
7045
+ 2110
8000
4000
7000

21. Very EASY when the addends have the same number of digits
8857
  4758
7045
8000
8857
  4758
7045
+ 2110
4000
7000
Draw the line after the
first number
In each addend.

22. Estimate to choose the most reasonable answer.
Between 11,000 and 15,000
Between 16,000 and 20,000
Between 20,000 and 25,000
Between 28,000 and 33,000
8000
  4000
7000
+2000

23. Use the front end estimation strategy.
247
6542
489
247
6542
489
240
6540
480

24. Estimate to find the best answer.
A little more than 7,000
A little more than 8,000
A little less than 9,000
A little less than 10,000
240
6540
480
7350

25. Use the front end estimation strategy.
5028
6732
1285
5000
5028
6732
1285
6700
1200

26. Estimate and choose the most reasonable answer.
Between 11,000 and 15,000
Between 16,000 and 20,000
Between 20,000 and 25,000
Between 28,000 and 33,000
5000
6700
1200
13700

27. Which one rounds to the highest place value?
3,876
5,814
3,176
+ 7,895
4,000
6,000
3,000
+ 8,000
3,000
5,000
+ 7,000

28. Which one rounds to the highest place value?
9,876
8,514
6,092
+ 3,895
9,000
8,000
6,000
+ 3,000
10,000
9,000
6,000
+ 4,000