Date post: | 21-Dec-2015 |
Category: |
Documents |
Upload: | stuart-wood |
View: | 217 times |
Download: | 3 times |
© 2007 M. Tallman
© 2007 M. Tallman
Find your number.Look right next door.
35
Step 1: Circle the digit in the place that you must round to.
Step 2: Draw an arrow to the place on the right.
Round to the nearest thousands place.
, 46
© 2007 M. Tallman
000346
Step 1: Circle the digit in the place that you must round to.
Step 2: Draw an arrow to the place on the right.
Step 3: If the number is four or less, then the circled number stays the same.
Step 4: All numbers to the right of the circled number become zeros.
4 or less, just ignore.
3 is less
than 4
Just Ignore!
5,
Round to the nearest thousands place.
© 2007 M. Tallman
7
Find your number.
Round to the nearest hundreds place.
Look right next door.
Step 1: Circle the digit in the place that you must round to.
Step 2: Draw an arrow to the place on the right.
53, 6
© 2007 M. Tallman
006765
4 or less, just ignore.5 or more, add 1 more.
7 is not less than
4
Step 1: Circle the digit in the place that you must round to.
Step 2: Draw an arrow to the place on the right.
Step 3: If the number is four or less, then the circled number stays the same.
Step 4: If the number is 5 or greater, then add 1 to the circled number.
Step 5: All numbers to the right of the circled number become zeros.
Round to the nearest hundreds place.
5 + 1 = 6
3,
© 2007 M. Tallman
When to use estimation…
When an exact answer is not needed.
When you need to compute a problem quickly.
To check your work.
© 2007 M. Tallman
486 + 130
5 1+ = 6Step 1: Rounding is always first. Decide which place to round to.
Step 2: Round each addend to the hundreds place.
00000 0
The actual answer is 616,
so our estimation is
pretty accurate.
The actual answer is 616,
so our estimation is
pretty accurate.
Step 3: Now you can add 500 and 100 mentally.
© 2007 M. Tallman
5,387 + 386
5,000 400+ =5,400
Step 1: Rounding is always first. Decide which place to round to.
Step 2: Round the first addend to the thousands place and the second addend to the hundreds place.
Step 3: Now you can add 5,000 and 400 mentally.
The actual answer is 5,773, so our estimation is pretty
accurate
Rounding Tip: The lower the place, the more accurate the answer. However, if you round too low, your problem may be more difficult to solve.
Rounding Tip: The lower the place, the more accurate the answer. However, if you round too low, your problem may be more difficult to solve.
Rounding Tip: The higher the place, the easier your problem will be to solve. However, your answer may not be as accurate.
Rounding Tip: The higher the place, the easier your problem will be to solve. However, your answer may not be as accurate.
© 2007 M. Tallman
5,400
5,387 + 386
5,000 400+ =5,400
Step 1: Rounding is always first. Decide which place to round to.
Step 3: Now you can add 5,400 and 400 mentally.
5,800
Step 2: Round the first addend to the thousands place and the second addend to the hundreds place.
© 2007 M. Tallman
44,897 + 26,578
40,000 30,000+ =70,000Step 1: Rounding is always first. Decide which place to round to.
Step 2: Round each addend to the ten thousands place.
Step 3: Now you can add 40,000 and 30,000 mentally.
The actual answer is
71,475, so our estimation is
pretty accurate.
The actual answer is
71,475, so our estimation is
pretty accurate.
© 2007 M. Tallman
$8.67 + $6.75
$9.00 $7.00+ =$16.00Step 1: Rounding is always first. Decide which place to round to.
Step 2: Round each addend to the nearest dollar.
Step 3: Now you can add $9.00 and $7.00, mentally.
The actual answer is
$15.42, so our estimation is
pretty accurate.
The actual answer is
$15.42, so our estimation is
pretty accurate.
© 2007 M. Tallman
1. $21.89 + $6.78
5,000
600100+500=
1,200500 +700 =
$27.00
4. 4,897 + 598
3. 145 + 467
Estimate Each Sum
2. 467 + 721
$20.00+$7.00=
5,600+600 =
© 2007 M. Tallman
5. 897,965 + 12,854
800,000
10,0006,000+4,000=
$350.00$50.00+$300.00=
910,000
8. 765,987 + 46,980
7. 5,897 + 4,465
Estimate Each Sum
6. $47.90 + $271.87
900,000+10,000=
850,000+50,000=
© 2007 M. Tallman
9. $8.75 + $3.98
200,000
38,0008,000+30,000=
$900.00$400.00+$500.00=
$13.00
12. 167,876 + 446,987
11. 8,321 + 32,432
Estimate Each Sum
10. $376.98 + $547.98
$9.00+$4.00 =
600,000+400,000=