Front End

1
Front End RoundingGwendolyn BestSuffolk
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
Roundingto the highestPlace Value
Round each number to its highest possible place
value. Some numbers will be rounded to ten-
thousands, thousands, hundreds, or tens.
8
26 1,427 216
What is the highest place value of each number?
375 Hundreds
26 Tens
1,427 Thousands
216 Hundreds

9
Round to the highest place.
375 Hundreds 400
26 Tens 30
1,427 Thousands 1,000
216 Hundreds 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 2110
8857   4758 7045 2110
9000
5000
7000
2000
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 92
247 6542 489 92
200
7000
500
90
14

• 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
• 90

15
Round each number to the highest place value?
5028 6732 1285 835
5000
5028 6732 1285 835
7000
1000
800
16
Front End Estimation
Estimation Strategy
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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 28
4,32 0 74 0 2,39 0 2 0
All numbers before the line stay the same.
19
26 1,427 216
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 2110
8857   4758 7045 2110
8000
4000
7000
2000
21
Very EASY when the addends have the same number
of digits
8857   4758 7045 2110
8000
8857   4758 7045 2110
4000
7000
2000
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 92
247 6542 489 92
240
6540
480
90
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
• 90

7350
25
Use the front end estimation strategy.
5028 6732 1285 835
5000
5028 6732 1285 835
6700
1200
800
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 800
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 3,000 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