This document provides examples and explanations for working with fractions, decimals, and percentages. It includes: 1) Warm-up questions covering converting fractions to decimals and finding percentages of numbers. 2) A mental math section to practice calculating percentages without a calculator. 3) Examples of setting up and solving percentage problems, including finding a number when given a percentage of it and finding the percentage when given the portion and total. 4) An example word problem about finding the total number of seats in a restaurant if the current number of people is a given percentage of the total.

1. December 11, 2014 Today:

2. Updates

3. Fraction, Decimal, & Percent Unit

5. Warm-Up:
1. F퐢퐧퐝 퐭퐡퐞 퐝퐞퐜퐢퐦퐚퐥 퐞퐪퐮퐢퐯퐚퐥퐞퐧퐭 퐨퐟 퐞퐚퐜퐡 퐟퐫퐚퐜퐭퐢퐨퐧:
ퟐퟏ
ퟏퟎퟎ
ퟏퟏ
ퟐퟓ
ퟓ
ퟗ
.21 .44 .55
These fractions represent the only three ways to convert fractions
to decimals. The denominator: a.) Is one of the place values
b.) Divides evenly into one of the place values: Multiply top
and bottom by that amount
c.) Either does not divide evenly into a place value, or you
are not sure: Divide the numerator by the denominator
ퟏ
ퟗ
Or, best of all, memorize , then multiply by 5.

6. Warm-Up:
2. 퐑퐞퐯퐢퐞퐰 퐅퐫퐨퐦 퐘퐞퐬퐭퐞퐫퐝퐚퐲: Write the Decimal equivalent
ퟑ
ퟓ
ퟐ
ퟏퟏ
ퟒ
ퟗ
ퟐ
ퟕ
ퟑ
ퟖ
4. What number is
ퟏ
ퟏퟎ
of
20?
3.
ퟏ
ퟏퟎ
is what
pWehrcaet n%t ?of 20 is
4 ÷ 20 = 4.2?0 =
20%
ퟐ
ퟕ
of 30 is what
ퟐ %?
ퟕ
of 50 is what
%?

7. Mental Math
Please do not say answer until asked so
others may have time to solve. thx.
Find 40% using mental math
Find 5% using mental math
1) 5 3) 80
1) 20 3) 70 4) 110
1) 30
3) 64
4) 120
Find 25% using mental math 1) 4) 160
10
3) 60
4) 90
2) 25
2) 20
2) 25
2) 48
Bonus Round: What is 95% of.. 50?

9. Solving Percent Problems

10. Percent IS
=
100 OF

12. % = is
100 of
20% of what number is 30?
20 = 30
100 x Cross multiply to find: 20x = 30(100)

13. What percent of 200 is 12?
% = is
100 of
x = 12
100 200
200x = 12(100)
200x = 1200
x = 6, so our answer is 6%

15. 2. Your restaurant has 3 people eating lunch now.
This is 15% of the total seats in the restaurant.
How many people can be seated at one time?

16. Example 3: Solve for the percent
=