1. Why did we say, do we use rounding?
The rule for rounding decimal places is the same as for other rounding rules, Let’s see!
Why did we say, do we use rounding?
To give an approximate answer
When we round to decimal places we can give an approximate answer which is more accurate than when we round to the nearest whole number, 10, 100 or 1000
Decimal places are the numbers after the point
Round to 1 d.p.  answer must have 1 number after point
Round to 2 d.p.  answer must have 2 numbers after point
Round to 3 d.p.  answer must have 3 numbers after point

2. Rounding To 1 Decimal Place
Round 4.67 to one decimal place (1d.p).
4.6
4.7
4.67
4.65
What number is the arrow pointing at ?
Mark 4.67 on the number line .
Is 4.67 closer to 4.6 or 4.7 ?
4.7
4.67 = 4.7 (to 1d.p)

3. Round to 1 d.p .
19.5
19.6
19.53
19.55
What number is the arrow pointing at ?
Mark on the number line .
Is closer to 19.5 or 19.6 ?
19.5
19.53 = 19.5 (to 1d.p)

4. Rounding to 1 Decimal Place (1DP)
5 or more?
5 or more?
5 or more? No No
Yes
4 . 8
4 . 8
4 . 9
5 or more?
5 or more?
5 or more?
Yes
Yes
Yes
4 . 9
5 . 3
2 . 0

5. Rounding to Decimal Places: 2DP
5 or more?
5 or more?
5 or more? No
Yes
Yes
5 or more?
5 or more?
5 or more? No
Yes
Yes

6. Rounding to Decimal Places: 3DP
5 or more?
5 or more?
5 or more?
Yes No
Yes
5 or more?
5 or more?
5 or more? No
Yes
Yes

7. Rounding to Decimal Places
1DP
2DP
3DP
5 or more?
5 or more?
5 or more?
Yes No
Yes
4 . 9
Copy &
complete
this table:
Number
To 1DP
To 2DP
To 3DP
63.5
63.47
63.472
87.7
87.66
87.656
Your Turn
150.0
149.99
3.5
3.54
3.540
0.6
0.60
0.600