STAGE 2
SKWIRK Brainiacs!
Unit
Topic
Chapter
Maths
Maths
Number
Rounding and Estimating
Beginners
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.
Round these two digit numbers to the nearest 10.
Number
Round to nearest
10
67
23
12
78
91
Round these three digit numbers to the nearest 10.
Number
Round to nearest
10
123
674
991
352
889
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.
Round these three digit numbers to the nearest 100.
Number
Round to
nearest
100
567
© 2010-2011 SKWIRK / Red Apple Education Pty Ltd
233
981
294
105
STAGE 2
SKWIRK Brainiacs!
Maths
Round these four digit numbers to the nearest 100.
Number
Round to
nearest
100
1235
4213
There are some rules for rounding
5567
9021
8923
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 these four digit numbers to the nearest 1000.
Number
Round to
nearest
1000
4672
8921
5777
1286
2209
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 10 then add the rounded numbers to make an estimate.
The first one has been completed for you.
Question
34 + 67 =
27 + 89 =
46 + 72 =
55 + 17 =
213 + 226 =
672 + 126 =
562 + 331 =
Round Numbers
30 + 70 =
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
Estimate
100