1. Starter Questions

2. To understand how to calculate a percentage using a calculator.
Percentages (Calculator)
Learning Intention
To understand how to calculate a percentage using a calculator.

3. Percentages (using a calculator)
By converting a percentage to fraction form, we can work out a percentage of an amount using a calculator.
Suppose we want to work out 38% of £65. 38
38% = =
38 ÷ 100
100
So we key in:
Remember money is 2 decimal places
3 8 8 ÷ 1 × 6 5 =
Explain that by converting the percentage to a decimal we can also work out percentages on a calculator.
It would be quite difficult to work out 38% of £65 without a calculator.
We can estimate the answer by working out 40% of £65. 10% of £65 is £6.50 so 40% is 4 × £6.50 = £26.
What is 38% as a decimal?
Ask pupils how we would write 24.7 in pounds before revealing the answer.
And get an answer of 24.7.
We write the answer as £24.70.

4. Percentages (using a calculator)
By initially writing a percentage as a decimal, we can work out a percentage using a calculator.
Suppose we want to work out 57% of £80.
57% =
0.57
So we key in:
Remember money is 2 decimal places . 5 7 × 8 =
Explain that by converting the percentage to a decimal we can also work out percentages on a calculator.
It would be quite difficult to work out 38% of £65 without a calculator.
We can estimate the answer by working out 40% of £65. 10% of £65 is £6.50 so 40% is 4 × £6.50 = £26.
What is 38% as a decimal?
Ask pupils how we would write 24.7 in pounds before revealing the answer.
And get an answer of 45.6.
We write the answer as £45.60.

5. Percentages (using a calculator)
Example You have to pay 8% of tax on fuel bills.
Calculate 8% of the following amounts
a) £250 b) £360 c) £190 d) £550

6. Percentages
Now try Ex 2.2
Ch2 Pg 14