Transcript Step 1

© 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 one (units).
4.37
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, or disappear.
Round to the nearest tenth.
00
4 .3
7
Just
Ignore!
3 is less
than 4
4 or less, just ignore.
© 2007 M. Tallman
4.37 rounded to the
nearest one (unit) is…
4
4.37
4
5
4.37 is closer to 4 on the number line.
© 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 one (units).
2 .8
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.
Round to the nearest one (units).
Step 3: If the
number is four or
less, then the circled
number stays the
same.
3 .8
2
0
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 decimal
number become
zeros, or disappear.
2+1=3
8 is not
less
than 4
54 or
or more,
less, just
add 1
ignore.
more.
© 2007 M. Tallman
2.8 rounded to the
nearest one (unit) is…
2
3
2.8
2.8 is closer to 3 on the number line.
© 2007 M. Tallman
3
17.4 + 4.8
The actual
answer is 22.2,
so our estimation
is pretty
accurate.
17 + 5 = 22
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round each
addend to the
nearest whole
number.
© 2007 M. Tallman
Step 3:
Now you can
add 17 and 5
mentally.
9.7 + 2.8
The actual
answer is 12.5, so
our estimation is
pretty accurate.
10 + 3 = 13
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round each
addend to the
nearest whole
number.
© 2007 M. Tallman
Step 3:
Now you can
add 10 and 3
mentally.
42.8 + 6.3
The actual
answer is 49.1, so
our estimation is
pretty accurate.
43 + 6 = 49
Step 1:
Rounding is
always first.
Decide which
place to round to.
Step 2:
Round each
addend to the
nearest whole
number.
© 2007 M. Tallman
Step 3:
Now you can
add 43 and 6
mentally.
Estimate Each Sum
1. 19.76 + 9.55
20 + 10 = 30
2. 7.45 + 8.56
7 + 8 = 15
3. 14.7 + 8.3
15 + 8 = 23
4. $23.87 + $6.70
$24.00 + $7.00 = $31.00
© 2007 M. Tallman
Estimate Each Sum
5. 13.56 + 4.4
14 + 4 = 18
6. 0.78 + 15.89
1 + 16 = 17
7. $9.33 + $102.5
$9.00 + $103.00 = $112.00
8. $4.77 + $28.70
$5.00 + $29.00 = $34.00
© 2007 M. Tallman
Estimate Each Sum
9. $3.26 + $14.67
$3.00 + $15.00 = $18.00
10. 6.42 + 33.31
6 + 33 = 39
11. $29.53 + $2.45
$30.00 + $2.00 = $32.00
12. 0.23 + 12.67
0 + 13 = 13
© 2007 M. Tallman