Finding Percentages with Calculators: Atomisation Made Easy

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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.