Finding Percents of numbers

Using the Is over Of technique in conjunction with drawing

percent bars

What do you think is the answer??

• Find 25% of 20

• Let’s draw a picture.

x

100% 20

25%

Can you solve this as a proportion? • Find 25% of 20

• What would the proportion look like?

100%

x25%

20

10025

20x

X = 5

We can do this Mathematically by using a special

proportion...just find the following...The Percent – it is the easiest to find.

Just look for the % sign!

The “Of” number - it is always just behind the word of. It represents the total (or the whole.)

The “Is” number – This represents the part or the piece of the whole. (It may be near the word “is.”

Finding is, of or a Percent

Find the missing number by drawing a bar and using the proportion.

a) 15% of 900 is what?

100

%=

of

isUse the proportion…

15%

100% 900

?

10015

900x

x = 135

Finding is, of or a Percent

Find the missing number by drawing a bar and using

the proportion.

b) What % of 84 is 63?

100

%=

of

is

x%

100 84

63

100%

8463

X = 75%

Finding is, of or a Percent

c) 35% of what # is 7?

100

%=

of

is

Find the missing number by drawing a bar

and using the proportion.

35%

100 ?

710035

x7

X = 20