rounding
Post on 01-Jan-2016
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Rounding
Intro 63.91 to Nearest Whole Number
Nearest Whole Number
Nearest Ten
Nearest Hundred
To 1 Decimal Place
Rounding By Interactive Example
Rounding Seven Questions
Rounding
When you use a tape measure to work out the length of a table often you give the answer to the nearest cm. This is known as ROUNDING You are often asked to ROUND an answer that you get on a calculator. What is 63.91 to the nearest Whole Number
63.0 63.1 63.2 63.3 63.4 63.5 63.6 63.7 63.8 63.9 64.0
0 1 2 3 4 5 6 7 8 9The “scale” shows numbers between 63 and
64.
Where is 63.9163.9
063.9
163.92 63.93 63.9
463.9
563.96 63.97 63.98 63.9
964.00
Can you see that 63.91 is closer to 64.0
Rounding 63.91 to a Whole Number
What is 63.91 to the nearest Whole Number
63.0 63.1 63.2 63.3 63.4 63.5 63.6 63.7 63.8 63.9 64.0
0 1 2 3 4 5 6 7 8 9
A What two WHOLE numbers is 63.91 between 63 and 64
B What is the figure after 63 9
9 is called the ROUND FIGURE
If Round Figure is 01234 ROUND to 63
The scale can be split into TEN sections using the ROUND FIGURE
If Round Figure is 56789 ROUND to 64 Answer 64
Round 15.5 to nearest Whole Number
Step 1 What is LOW
Step 2 Next Figure is Round Figure
15
5
Step 3 If the Round figure is 0 or 1 or 2 or 3 or 4 then round to LOW
ROUND to 16
1615.5 to nearest whole number is
1 5 . 5
1 5 . 5
Whole number
Hide the decimal part to get LOW
Round Figure
No!
Sep 4 The Round figure is 5 or 6 or 7 or 8 or 9 so round to High
After 15 is 16
Round 28.3 to Nearest whole number
Step 1 What is LOW
Step 2 Next Figure is Round Figure
28
3
Step 3 If the Round figure is 0 or 1 or 2 or 3 or 4 then round to LOW
ROUND to 28
2828.3 to nearest whole number is
2 8 . 3
2 8 . 3
Whole number
Hide the decimal part to get LOW
Round Figure
Yes!
Round 89 to nearest Ten
Step 1 What is LOW
Step 2 Above 1st 0 is Round Figure
80
9
Step 3 If the Round figure is 0 or 1 or 2 or 3 or 4 then round to LOW
ROUND to 90
9089 to nearest Ten 8 9
8 9
10, 20, 30 ….. Must end in a 0 ….. Figure before Units Plus 0
Round Figure
No!
Step 4 The Round figure is 5 or 6 or 7 or 8 or 9 so round to High
80 + 10 is 90
0
Round 324 to nearest Ten
Step 1 What is LOW
Step 2 1st Figure to be replaced is Round Figure
320
4
Step 3 If the Round figure is 0 or 1 or 2 or 3 or 4 then round to LOW
ROUND to 320
320324 to nearest Ten 2 4
2 4
10, 20, 30 ….. Must end in a 0 ….. Figure before Units Plus 0
Round Figure
Yes!
0
3
3
Round 1995 to nearest Hundred
Step 1 What is LOW
Step 2 Above 1st 0 is Round Figure
1900
9
Step 3 If the Round figure is 0 or 1 or 2 or 3 or 4 then round to LOW
ROUND to 2000
2001995 to nearest Hundred 1 9
9 5
100, 200, 300 ….. Must end in a 00 ….. Figure before Tens Plus 00
Round Figure
No!
Step 4 The Round figure is 5 or 6 or 7 or 8 or 9 so round to High
1900 + 100 is 2000
0
9 5
91
0
Round 9.95 to 1 Decimal Place
Step 1 What is LOW
Step 2 Next Figure is Round Figure
9.9
5
Step 3 If the Round figure is 0 or 1 or 2 or 3 or 4 then round to LOW
No!
10.09.95 to 1dp is 9 . 9 5
9 . 9 5
1dp
Cover number then move to the right until there is one figure after the point
Round Figure
Step 4 The Round figure is 5 or 6 or 7 or 8 or 9 so round to High
After 9.9 is 10.0
ROUND to 10.0
Round 8.832 to 1 Decimal Place
Step 1 What is LOW
Step 2 Next Figure is Round Figure
7.8
3
Step 3 If the Round figure is 0 or 1 or 2 or 3 or 4 then round to LOW
ROUND to 7.8
7.87.832 to 1dp is 7 . 8 3 2
7 . 8 3 2
1dp
Cover number then move to the right until there is one figure after the point
Round Figure
Rounding … By Example
0 1 2 3 4
5 6 7 8 9
C
.
÷x
0+ On
²
-
Ans
=
√(-)
600 610 620 630 640 650 660 670 680 690 700
Round 672 To Nearest Hundred
6 2
0 1 2 3 4 5 6 7 8 9
Low High
Click Round Fig
Start
Is between and
Show Scale
7
Nearest Hundred
ROUND
990
762
194
927
885
981
436
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Next
Nearest Hundred
To Nearest Hundred
Show Ans 0 1 2 3 4
5 6 7 8 9
C
.
÷x
0+ On
²
-
Ans
=
√(-)
C
0
1 2 3
4 5 6
7 8 9
C
.
÷
x
0
+
On
²
-
Ans
=
√
(-)
0 1 2 3 4
5 6 7 8 9
C
.
÷x
0+ On
²
-
Ans
=
√(-)Test
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