Finding a percentage of a number

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 1

Finding a percentage of a number

Objectives:

you will be able to calculate a percentage of a given number using different methods (proportion method, decimal method, and fraction method).

Percentage 

a percentage represents a fraction out of 100.

Percentage 

a percentage represents a fraction out of 100.

Percentages can also be represented in decimal or fraction form

Proportion method:

Example: What is 30% of 200?

Proportion method:

Example: What is 30% of 200?

​100​​30​​=​200​​x​​

Proportion method:

Example: What is 30% of 200?

​100​​30​​=​200​​x​​

Solve for x

Proportion method:

Example: What is 30% of 200?

​100​​30​​=​200​​x​​

Solve for x

x=60

Decimal method:

Example: What is 30% of 200?

0.3

Decimal method:

Example: What is 30% of 200?

0.3 x 200 = 60

Fraction method:

Example: What is 30% of 200?

​100​​30​​

Fraction method:

Example: What is 30% of 200?

​100​​30​​⋅200=60

Find 18% of 850

Calculate 6.7% of 300

Find 2.4% of 620

Calculate 43.9% of 780

A student answered 75% of 120 questions correctly. How many did they get right?

A store offers a 15% discount on a €250 phone. How much is the discount?

A product originally cost €90. After a 30% increase, what is the new price?

I can calculate a percentage of a given number

😒🙁😐🙂😃

What is the difference between percentage of and percentage off?

What is the difference between percentage of and percentage off?

"Percentage of" → Finding a portion of something (e.g., "20% of my salary").

"Percentage off" → Reducing from the original value (e.g., "20% off a product means you pay less").