Why do we multiply by 100 to turn a decimal into a percent? Question of the day

agenda Comprehension check Flow chart check Class exercise Part of whole percent notes ( very short) Review questions

Comprehension check 100% 0.0825 6.25 1 8 % 2 300 33.3% 3 4 100 250% Fraction Decimal Percent   100% 0.0825 6.25 1 8 % 2 300 33.3% 3 4 100 250% 0.005 150 100 5 1 2 100 0.055 5 1 2 %

To find what percent To find out what percent part of a group is compared to the whole group you can: Write a proportion 𝑝𝑎𝑟𝑡 𝑤ℎ𝑜𝑙𝑒 = 𝑋 100 Or Write equation part ÷ whole=quantity X 100 There are 13 girls in Mrs. Flynn’s fifth period and 11 boys. What percentage of her class is girls?

You try Gray middle school has 362 sixth graders, 336 seventh graders and 362 eighth graders. What percentage of Gray is in the seventh grade?

Class exercise What percentage of our class is girls? What percentage of our class is wearing jeans? What percentage of our class is blond? What percentage of our class is a wearing a mostly white shirt?

Discounts Discount is the amount (usually money) that is taken off from an original amount There are also two ways to find what the discount should be 1) you can write a proportion 𝑝𝑎𝑟𝑡 𝑤ℎ𝑜𝑙𝑒 = % 100 2) you can write equation part ÷ whole=quantity X 100 Since Wendy works for Flynnland Park, she gets a 15% discount. She is buying a “Flynn Rules” T-shirt that costs $20. What will be the discount? %= 15 100=100 (this is always true) Part = unknown Whole = $20 the original cost

solve 𝑝𝑎𝑟𝑡 𝑤ℎ𝑜𝑙𝑒 = % 100 𝑥 20 = 15 100 100𝑥 100 = 300 100 %= 15 100=100 (this is always true) Part = unknown Whole = $20 the original cost 𝑝𝑎𝑟𝑡 𝑤ℎ𝑜𝑙𝑒 = % 100 𝑥 20 = 15 100 100𝑥 100 = 300 100 X=3 so the discount is $3.00

Now we know the discount Know the discount is $3.00, we subtract it from the original cost $20.00 - $3.00 So after the discount her shirt will cost $17.00

Markdowns are done the same way A store has decided to mark down all their sofas by 20%. If a sofa costs $750 what would the cost be after the markdown? You try

assignment Ask ten people these three questions. ( make sure they answer yes or no) Record your results Find the percentage of yes and no’s for each question 1) Are you older than 18? 2) Is football your favorite sport? 3) Does you phone number start with a 3?