STAGE 2
SKWIRK Brainiacs!
Unit
Topic
Chapter
Maths
Maths
Number
Rounding and Estimating
Intermediate
Rounding and Estimating
We use rounding to work out the approximate answer to a question. It rarely gives us the
exact answer. We round numbers to make an estimate on an answer.
There are some rules for rounding
numbers to the nearest 10
If the last digit in the number is less than 5 (0, 1, 2, 3 or 4), we round down.
If the last digit in the number is 5 or more (5, 6, 7, 8, or 9), we round up.
There are some rules for rounding
numbers to the nearest 100
If the last two digits in the number are less than 50 we round down.
If the last two digits in the number are 50 or more we round up.
There are some rules for rounding
numbers to the nearest 1000
If the last three digits in the number are less than 500 we round down.
If the last three digits in the number are 500 or more we round up.
Round each number to the nearest 10
Number
345
223
4678
2219
3467
2409
Round up

Round down
Rounded Number
350
Round these numbers to the nearest 10 and to the nearest 100.
Number
89
123
459
331
458
8923
3391
2011
247
1099
© 2010-2011 SKWIRK / Red Apple Education Pty Ltd
Round to the nearest 10
Round to the nearest 100
SKWIRK Brainiacs!
STAGE 2
Maths
We can round numbers to make estimations. An estimate is a
good guess or a good try at working out the answer to a problem.
It probably won’t give you the exact answer to a problem but it
will give you a rough idea of the answer.
Round each number to the nearest 100 then add the rounded numbers to make an
estimate. The first one has been completed for you.
Question
349 + 672 =
907 + 249 =
226 + 872 =
551 + 217 =
213 + 816 =
902 + 126 =
422 + 211 =
Round Numbers
300 + 700 =
Estimate
1000
Round each number to the nearest 100 then add the rounded numbers to make an
estimate. The first one has been completed for you.
Question
4922 + 1022 =
3891 + 3661 =
1209 + 2001 =
2219 + 2390 =
3361 + 9021=
9121 + 2861 =
2391 + 4561 =
Round Numbers
4900 + 1000 =
Estimate
5900
Round these amounts of money to the nearest dollar. The first one has been
completed for you.
Amount of money
$2.36
$8.17
$9.08
$1.67
$2.03
$8.09
$2.56
Rounded to
nearest dollar
$2.00
My Learning points!




To be able to round numbers to the nearest 10
To be able to round numbers to the nearest 100
To be able to round numbers to the nearest 1000
To make estimates by rounding numbers
© 2010-2011 SKWIRK / Red Apple Education Pty Ltd