GCSE Maths - Percentage Increase and Decrease (Multiplier Method) #93

This video tutorial explains how to calculate percentage increases and decreases using two methods: a simple, intuitive technique and a more advanced multiplier method. It covers step-by-step examples for both increasing and decreasing values by a percentage, including real-world applications like discounts. The tutorial also highlights common mistakes and special cases, such as handling percentage changes less than 10% or more than 100%.

What is the first step in increasing a number by a percentage using the simple method?

• Divide the number by the percentage

• Add the percentage directly to the number

• Subtract the percentage from the number

• Convert the percentage to a decimal and multiply by the number

If a product costs £142 and has a 12% discount, what is the discounted price?

• £130.00

• £120.00

• £124.96

• £140.00

In the multiplier method, how do you represent a 40% increase as a decimal?

• 1.4

• 0.04

• 4.0

• 0.4

What is the multiplier for decreasing a number by 30%?

• 0.3

• 1.3

• 0.7

• 1.7

When decreasing a number by 3%, what is a common mistake to avoid?

• Multiplying by 100

• Adding instead of subtracting

• Using 0.3 as the multiplier

• Using 0.03 as the multiplier

How do you calculate a 250% increase using the multiplier method?

• Multiply by 2.5

• Multiply by 0.25

• Multiply by 1.25

• Multiply by 3.5

What is the new value when increasing 450g by 18% using the multiplier method?

• 531g

• 500g

• 450g

• 480g