Percent of Number & Finding Whole Given Part and Percent

​Finding a percent of a number

and

Finding a whole given part and %​

Percent of a number

Example: What is 30% of 180?

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Example: Walmart is having a clearance sale of 25% of everything. If I buy a new bike that costs $400, how much will I save?

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Example: A bag of skittles has 60 pieces in it. 10% of the skittles are purple. How many pieces are purple?​

Subject | Subject

​Percent of a number

How do I find a percent of a number?!?

​ - Example: What is ​25% of 400?

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Step 1: Change your percent into a decimal​

Fill in the Blanks

What is 25% written as a decimal?

​percent of a number

​How do I find a percent of a number?!?

​ - Example: What is ​25% of 400?​

Step 1: Change your percent into a decimal​ ---> 0.25 or .25

Step 2: Multiply your decimal (.25) by the whole number (400)

• 0.25 x 400 = ​

Fill in the Blanks

What is 0.25 x 400?

Percent of a Number

​​How do I find a percent of a number?!?

​ - Example: What is ​25% of 400?​

Step 1: Change your percent into a decimal​ ---> 0.25 or .25

Step 2: Multiply your decimal (.25) by the whole number (400)

• 0.25 x 400 = ​100

​So...25% of 400 is 100.

Finding a Whole Given % and Part

Examples:

• 5 is 10% of what number?

• There are 16 boys in the classroom. This is 80% of the class. How many total students are in the classroom?​

  • Here, we have a part and a percent. We know we have a part because percent is always out of 100%. We do not have 100% in these type of problems!​ The problems are saying the number we have is that percentage.

Finding Whole Given Part and %

Example: 5 is 10% of what number?

• This problem is stating 5 = 10%. We should recognize that ​since

  5 = 10%, we are missing the whole number.

• Step 1: write your equation of % x whole = ​part

  • 10% x whole = 5

• ​Step 2: change your percent into a decimal

Fill in the Blanks

What is 10% written as a decimal?

Finding whole given part and %

Fill in the Blanks

What is $\frac{5}{.10}$  ?

Finding whole given part and %

Some text here about the topic of discussion

How Do I Know Which Problem is Which?

Finding Percent of a Number vs Finding a Whole Given Part and Percent

• Finding a percent: the problem gives you a percent and a number. The number is the whole number and we are trying to find what number the percentage represents. What is 10% of 100. The word of means what part of 100 is 10%

Finding Whole Given Part and Percent

• Here, the Percent is the number given. 20 is 10% of what number?

  • The sentence is saying 20 = 10%...we know that percent is out of 100% so 20 is not the whole. It is also saying that of what number? Meaning the missing number is the big/whole number!

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Fill in the Blanks

What is 40% of 200? (Remember, the word OF means 40% is what part of 200? Meaning we already have the whole. We are trying to figure out what number does the percent represent.)

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25 is 20% of what number? (Remember: this is saying that 25 = 20%, and we know 20% is not a whole because 100% is a whole. Meaning, we need to find the whole.)

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63 students are in the band. This represents 70% of the grade. How many students are in the entire grade? (Remember, this is saying that 63 students = 70%. This is not 100% meaning it is a part of the grade. We need to find how many students are in the whole grade.)

Fill in the Blanks

In a group of 30 kids, 80% of them can swim. How many students can swim? (Remember: the group size is 30, we are trying to figure out what percentage of them can swim.)