Transcript Slide 1 - percentdotcom

Percent DOT.com
Calculating and Using percent in
the Real World
DOGGONE MATH LYRICS
Music and Lyrics by Harry Guffee
Copyright 2002 Harry Guffee/BMI
PERCENT
Percent comes from the Latin words per
centum
Which means parts in a hundred, so you see
A penny is one cent out of a hundred
A hundred years are in a century
To calculate percent of any number
Multiply the number times percent
Times a decimal; times a fraction
As long as they are all equivalent
One percent is one part in a hundred
Ten percent is also one in ten
A centipede is thought to have a hundred legs
Centurions control one hundred men
Percents can also be expressed as fractions
One fourth is also twenty-five percent
Or twenty-five one hundredths
Or “point twenty-five”
As long as they are all equivalent
Look around - % is there
Discount
Sales Tax
There are many uses for
percent
Calculating the Tip
Nutritional Information
Finding the Percentage
Freddie sold $160 worth of video games to a friend. He kept 15%
of the money for himself and put the rest in the bank. How much
did he keep for himself?
To find the percentage of a number
15% of 160
Change the percent to fraction or a decimal
.15 X 160
Multiply
15% of $160 = $24
Need more help?
If you sit in a shopping mall long enough, it is almost a certainty that you
will hear someone say, "What is 25% of $60 or what is 40% of $30?"
The first step in calculating the percent of numbers is to change the
percent to a decimal. When you see the word "of" in word problems, that
signals multiplication, so take the decimal and multiply by the number.
Example: Find 25% of $60.
.25 x 60 =$15
By changing the percent to a decimal and translating the word "of" to
multiplication we have a simple solution.
Example: Find 40% of $30.
.40 x 30 = $12
We can now discuss sales price and
discount.
A suit is regularly priced at $120, and it
is marked 20% off the regular price.
What is the new price for the suit?
Follow the previous examples and begin
by taking 20% of $120.
20% of $120 = .20 x 120 = $24.00
We call $24 the discount.
We calculate the sales price by taking
the regular price $120 and subtracting
the discount $24…
$120 – $24 = $96
The sales price and cost of the dress is
therefore $96.
Addition tutorials can be found at
(Click percent sign to navigate to internet site)
Pearson Prentice Hall Mathematics Video
School Tube – Finding Percent of a Number
Mathplayground – How to Find Sales Price
Can you score 100% ?
What is 25% of 320?
(Click on Answer to display)
Answer: 80
What is 45% of 86?
(Click on Answer to display)
Answer: 38.7
Games
http://www.mathplayground.com/balloon_invaders_percent.html
http://www.mathplayground.com/percent_shopping.html
www.mathplayground.com/mathatthemall2html
www.bbc.co.uk/.../fractiondecimal/percentage/
www.kidsmathonline.com/numbers/percentages.html
What percentage of the DOTS are orange?
What percentage of the DOTS are red?
What percentage of the DOTS are upside down?
Fun Spot Dots and
Percentage
DOTS were introduced in 1940 by Mason and trademarked
that year. In 1972, Tootsie Roll Industries acquired the DOTS brand by
purchasing the Mason Division of Candy Corporation of America.
Take a tour of the Tootsie Roll factory to see how the Dots candies are made.
http://www.tootsie.com/gal_tour.php
Fun Spots Dots and
percentage
Answer:
• 40% of the DOTS are orange.
• 60% of the DOTS are red.
• 35% of the DOTS are upside down.
Acknowledgements
• Music
• DOGGONE MATH LYRICS: Music and Lyrics by Harry
Guffee; Copyright 2002 Harry
• Guffee/BMI
• References:
• Pearson Prentice Hall Mathematics
• SchoolTube
• Schoolplayground.com
• Kidsmathonline.com
• Last Brain Thinking
• Tootsie Roll Industries
• Created by C. M. Usauskas 4/2011