1. Starter Questions
47º

2. To round numbers to the nearest 10, 100 and 1000.
Whole Numbers
Learning Intention
To round numbers to the nearest 10, 100 and 1000.

3. There are 1432 pupils at Eastpark Secondary School.
Whole Numbers
We do not always need to know the exact value of a number.
For example,
There are 1432 pupils at Eastpark Secondary School.
There are about one and a half thousand pupils at Eastpark Secondary School.
Talk about rounding in real life contexts, for example the number of people at a football match. Ask pupils to give examples.
State that we can also use rounding in maths to give approximate answers to calculations.
We can round numbers to the nearest 1000, 100, 10, whole number, 0.1, etc. depending on the level of accuracy required.

4. Whole Numbers
Use the slider to show a variety of readings from each scale.
Use the measuring cylinder to round reading to the nearest 10ml, the scales to round numbers to the nearest 10g or 100g and the thermometer to round numbers to the nearest 10oC including negative amounts.
Introduce the convention of rounding up half-way values.
Link:
S7 Reading scales

5. Whole Numbers Rounding to nearest 10, 100 and 1000
“If It’s 5 or above give it a shove
If it’s 4 or below keep it low”
To round to the nearest 10 : look at the units digit:
- If it is a 0, 1, 2, 3, 4 leave the 10’s digit as it is.
- If it is a 5, 6, 7, 8, 9 round the 10’s digit up by 1.
To round to the nearest 100 : look at the tens digit:
- If it is a 0, 1, 2, 3, 4 leave the 100’s digit as it is.
- If it is a 5, 6, 7, 8, 9 round the 100’s digit up by 1.

6. Whole Numbers Rounding to nearest 10, 100 and 1000
To round to the nearest 1000 : look at the hundreds digit:
- If it is a 0, 1, 2, 3, 4 leave the 1000’s digit as it is.
- If it is a 5, 6, 7, 8, 9 round the 1000’s digit up by 1.

7. Whole Numbers Example Round 34 871 Round 34 871
Round to the nearest 100.
Look at the digit in the hundreds position.
We need to write down every digit up to this.
Look at the digit in the tens position.
Talk through the example.
Note that is not equal to is an approximation. We must include ‘to the nearest 100’ to ensure that the equals sign is not used incorrectly.
If this digit is 5 or more then we need to round up the digit in the hundreds position.
Solution:
34871 = (to the nearest 100)

8. Whole Numbers Complete this table: 37521 38000 37500 37520 274503
to the nearest 1000
to the nearest 100
to the nearest 10
37521
38000
37500
37520
274503
275000
274500
274500
Talk through each answer in the table.
9875
10000
9900
9880
452
500
450

9. Whole Numbers Now try Ex 5.1 Ch1 Pg 9
Rounding to nearest 10, 100 and 1000
Now try Ex 5.1
Ch1 Pg 9