Morning/ Afternoon Work
Rounding for Estimation.
We can use rounding numbers to get a rough idea or an estimate.
An estimate might be a little more or a little less than the actual amount.
By carrying out an estimate we can check that the answers to problems are sensible.
If you were buying 9 identical shirts for the school’s sports team that cost £7.80 each, to get a rough idea of the total cost you could round up £7.80 to £8.00.
You could also round up 9 shirts to 10 shirts.
Your calculation would then be: 10 × £8.00 = £80.00
Example
You can use rounding when you’re buying things in a shop:
1. You’ve bought 11 pens at 95p each. To check how much you should be charged, you could round down 11 to 10 pens and round up 95p to £1.00.
2. The estimated cost would then be 10 × £1.00 = £10.00.
3. The cashier charges you £10.45, the correct amount, which is close to the estimate.
Your Questions
