Understanding Percentage Changes with Multiplication

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Understanding Percentage Changes

What do you already know about using decimals to calculate percentage increases and decreases?

Learning Objective

At the end of the lesson you will be able to use decimals to calculate percentage increases and decreases, and identify what % change a multiplier represents.

What Are Multipliers in Maths?

A multiplier is a decimal or fraction used to represent a percentage when calculating an increase or decrease. Example: 0.87 or 1.06.

Multiplying by Less than 1

0.87 x 480 means you are finding 87% of 480. It is also the same as reducing 480 by 13%.

Multiplying by More than 1

1.06 x 290 means you are finding 106% of 290. It is also the same as increasing 290 by 6%.

Quick Reference Table

0.87 x Number = 87% of number = 13% decrease 1.06 x Number = 106% of number = 6% increase

How To Calculate

Multiply the original by the decimal to find the new amount after the percentage change.

Multiplier Form

Try It Yourself: Fill in the Blanks

1. 0.87 x 480 can be used to calculate ___% of 480. 2. 0.87 x 480 can also reduce 480 by ___%. 3. 1.06 x 290 can be used to calculate ___% of 290. 4. 1.06 x 290 can also increase 290 by ___%.

Reflection: Why Use Multipliers?

Multipliers make it quick and simple to do percentage calculations. Where else could you use this in real life? For example, think about shopping sales or tax.

Write down 3 things you learned in this lesson.

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