Percents - Find the Part!

I can figure out the part of an equation if I have the percent and the whole.

6.NS.8 Interpret, model, and use ratios to show the relative sizes of two quantities. Describe how a ratio shows the relationship between two quantities. Use the following notations: a/b, a to b, a:b.

CCSS.MATH.CONTENT.6.RP.A.3.C

Find a percent of a quantity as a rate per 100 (e.g., 30% of a quantity means 30/100 times the quantity); solve problems involving finding the whole, given a part and the percent.

You have a pile of pennies that you want to count.  When the pennies are put in groups of 2 there is one penny left over. When they are put in groups of three, five and six there is also one penny left over. But when they are put in groups of seven there are no pennies left over. How many pennies could there be?

How will you start solving this problem?

How can you be sure you are right?

Is there only one answer, or are there many?

Words - 60 percent

Percent symbol (%) 60%

Fraction  $\frac{75}{100}$  

(Also, it can be a decimal .75)

75% can also be shown in Fraction Form

 $\frac{75}{100}$  this can be simplified  by dividiing by the GCF

 $\frac{75\div25}{100\div25}=\frac{1}{4}$  so  $\frac{75}{100}$ and  $\frac{1}{4}$  are equivalent.

Any percent can be written as a fraction and a decimal

30% =  $\frac{30}{100}$   

 $\frac{30}{100}\ written\ as\ a\ decimal\ is\ .30$  

So, to write a percent as a decimal move the decimal two places to the left and drop the percen symbol.  30% = .30

There are three parts in any percent statement: the whole, the part, and the percent.

For example: 16 is 20% of 80. 80 is the whole amount, 16 is the part, and 20% is the percent.

There are 20 people in the library. Twelve of them are children. 60% of the people in the library are children.

What number is the part? What number is the whole? What is the percent?

Part = 12, Whole = 20, Percent = 60%

Part = Percent x Whole or 12 = 60% x 20

Part = Percent x Whole

25 = .25 x 100

(Remember your fact families!)

Write the percent as a decimal

Determine what you know and what you need to find (part, whole percent).

Make a variable the unknown

Set up the equation

Simplify (solve)

Percentages can be shown in different ways

Written: 35 percent

Percent sign: 35%

Fraction  $\frac{35}{100}or\ \frac{7}{20}$  

Decimal   0.35

Write the percent as a decimal

Determine what you know and what you need to find (part, whole percent).

Make a variable the unknown

Set up the equation: part = percent x whole

Simplify (solve)