Percent

1
Percent

• Working with a unit square

http//illuminations.nctm.org/LessonDetail.aspx?ID
L249
2
What are 4 ways to write a number?

• Decimal
• 0.001
• Fraction
• 1/1000

• Percent
• 0.1
• Scientific Notation
• 1.?10-3

3
Introducing the Unit Square

• The unit square represents the whole (100)
• Each small box represents 1

10 Boxes
10 Boxes
4
What Percents are Represented?
5
And a Few More.
6
Using the Unit Square

• What quantity does the whole unit square
  represent?

• What quantity does one small box represent?

7
Calculating Using the Unit Square

• How many people are represented by
• ½ the unit square?
• 20 small squares?
• 33.5 squares?

• What part of the unit square would represent
• 100 people?
• 48 people?
• 78 people?

8
Going the Other Way

• If you know the size of a small box you can find
  the size of the unit square

2.5

• If 12 of the class is 30 people, 1 of the class
  is 2.5 people, so the whole class (100) is 250
  people.

9
So how much does it cost?
Is a discount of 30 off, followed by a discount
of 50, the same as a discount of 80 off the
initial price?
http//www.figurethis.org/challenges/c17/challenge
.htm