Transcript Step 1 - s3.amazonaws.com

© 2007 M. Tallman
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.
4,389
Findright
yournext
number.
Look
door.
© 2007 M. Tallman
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.
Round to the nearest thousands place.
000
4,389
Just
Ignore!
3 is less
than 4
4 or less, just ignore.
© 2007 M. Tallman
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 hundreds place.
3,57 1
Findright
yournext
number.
Look
door.
© 2007 M. Tallman
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.
3, 5
67
1
00
5+1=6
7 is not
less than 4
or more,
less, just
54 or
add ignore.
1 more.
© 2007 M. Tallman
72 × 47
1
2
The actual
answer is 3,384,
so our estimation
is pretty
accurate.
1 2
70 × 50 = 3,500
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round 72
and 47 to
the nearest
ten.
Step 3:
“Box” and
solve the
basic math
fact.
© 2007 M. Tallman
Step 4:
Count the zeros
in both factors.
Place the zeros
in the product.
578 × 63
1 2
The actual
answer is 36,414,
so our estimation
is pretty
accurate.
3
1 2 3
600 × 60 = 36, 000
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round 578 to the
nearest hundred
and 63 to the
nearest ten.
© 2007 M. Tallman
Step 3:
“Box” and
solve the
basic math
fact.
Step 4:
Count the zeros
in both factors.
Place the zeros
in the product.
$45 × 785
1
2 3
1 2 3
$50 × 800 = $40, 000
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round $45 to the
nearest dollar and
785 to the
nearest hundred.
© 2007 M. Tallman
Step 3:
“Box” and
solve the
basic math
fact.
Step 4:
Count the zeros
in both factors.
Place the zeros
in the product.
57 × 7,342
1
2 3 4
1 2 3 4
60 × 7,000 = 420,000
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round 57 to the
nearest ten and
7,342 to the
nearest thousand.
© 2007 M. Tallman
Step 3:
“Box” and
solve the
basic math
fact.
Step 4:
Count the zeros
in both factors.
Place the zeros
in the product.
435 × 289
1 2
3 4
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round 435
and 289 to
the nearest
hundred.
1 2 3 4
400 × 300 = 120,000
© 2007 M. Tallman
Step 3:
“Box” and
solve the
basic math
fact.
Step 4:
Count the zeros
in both factors.
Place the zeros
in the product.
Estimate Each Product
1. $21.89 × $6.78
$20.00 × $7.00 = $140.00
2. 767 × 721
800 × 700 = 560,000
3. 145 × 467
100 × 500 = 50,000
4. 4,897 × 598
5,000 × 600 = 300,000
© 2007 M. Tallman
Estimate Each Product
5. 92 × 2,228
90 × 2,000 = 180,000
6. $72 × 679
$70 × 700 = $49,000
7. 8,432 × 467
8,000 × 500 = 4,000,000
8. $2,197 × 45
$2,000 × 50 = $100,000
© 2007 M. Tallman
Estimate Each Product
9. 789 × 567
800 × 600 = 480,000
10. 27 × $8,567
30 × $9,000 = 180,000
11. 3,467 × 77
3,000 × 80 = 240,000
12. 8,813 × 98
9,000 × 100 = 900,000
© 2007 M. Tallman