Finding Percentages with Calculators
Finding Percentages with Calculators
What do you already know about finding percentages of numbers?
Learning Objective
At the end of the lesson you will be able to find a percentage of a given amount using a calculator and atomisation.
What is a Percentage?
A percentage is a way of showing a fraction out of 100. It makes comparing amounts easier.
Why Use a Calculator?
Calculators help you work out percentages quickly and accurately, especially with larger numbers.
Steps to Find a Percentage
Step 1
Step 2
Change the percentage to a decimal or fraction.
Multiply by the amount using a calculator.
Atomisation Method
Atomisation means breaking the calculation into simple steps. For example: 25% of 80 → 0.25 × 80 = 20.
Worked Example
Find 15% of 200 using a calculator. Type 0.15 × 200 = 30.
Try It Yourself
What is 40% of 150? Use the atomisation steps and your calculator.
Check Your Answer
Did you get 60? 0.40 × 150 = 60.
Common Mistakes to Avoid
Wrong Operation
Remember: 25% = 0.25, not 2.5.
Always multiply; don’t add or subtract.
Wrong Decimal
Now You Practise!
Use a calculator to find: What is 12% of 500? What is 65% of 80? Remember your steps: convert, then multiply.
Write down 3 things you learned in this lesson.
Write down 2 things you want to know more about.
Ask 1 question about something you haven't quite understood yet.