1. Today: December 10, 2014
Warm-Up
Using the GCF to Reduce or Factor
 Percent: Definition, Purpose & Use
Mental Math With Percent
Class Work: Focus on Fractions

2. Fraction, Decimal,
& Percent Unit

3. Warm-Up:
1. Before working this problem, look at/analyze it, then
describe your plan to solve based on what you see in this
particular problem. Be specific, use complete sentences. Do
not solve yet.
1. -3n2 + 7n
n
Because there is more than one term, I’m going to simplify
by factoring. I will cancel factors from the numerator &
denominator if I can
______________________________________________
_____
______________________________________________
_____
_________________.

4. Warm-Up:
2. Same directions for this problem:
2.
퐱+ ퟑ
ퟐ
+
퐱+ퟐ
ퟓ
=
ퟏ ퟑ
ퟑ = 3
ퟏퟎ
ퟐퟏ
________________________________________
____________________________________________
________________________________________
This is not a proportion, so I’ll have to multiply
each term by the LCD to eliminate the
denominators.
Then I’ll combine like terms and solve as usual.
3. Which fraction must have more than two decimal places?
Why??
Because six does not go evenly into 100.
A.) ¼ B.) 2/5 C.) 12/50 D.) 5/6 E.) None

5. Warm-Up:
Simplify:
5. 10m – 15n
5
6. 20a6b5
35a2b3
7. 15x2 + 21x6
9__
2(x – 1)
7. 45
10x – 10
2
3
= ?_
18

6. Khan
Review:

7. Decimal: Latin decimalis, meaning tenths. Root is Latin
decim, ten.
 English: Decade, December? October?
 A decimal is a fraction with a denominator that
is also a place value.
Decimals and fractions cannot be mixed in the same
number
ퟑ.ퟓ
ퟒ

8. Percent: Definition
 Percent: From the Latin per centum. Per: for each as in
"One per student.” Centum: hundred Century, Cent,
Centimeter, Centipede
100% = 100 = 1
100
50% = 50 =
ퟏ
ퟐ
= .5
100
5% = 05 = 1 = .05
100 20
**Fractions, Decimals, & Percents are three different ways of
expressing the same amount. All three show a single number
based on the relationship (ratio) between two other
numbers.

9. Fractions Decimals Percent
Since the % sign cannot be +, -, x, ÷; numbers expressed as
percents must be changed to a decimal or fraction before
any calculations can be made.
 A. How to change a decimal to a percent:?
Move the decimal 2 places to the right and add the % sign.
 B. How to change a percent to a decimal:?
Move the decimal 2 places to the left and drop the % sign.
 C. How to change a fraction to percent, or percent to
fraction?
To change a fraction to percent, or percent to fraction, the
number must be changed to a decimal first.

10. Fractional Conversions:
Fraction Decimal Percent
0.5 50
0.33 33.3
0.25 25
0.20 20
0.16 16.7
0.1428571 14
0.125 12.5
0.11 11
0.09 9

11. Mental Math:
Percent of a Number
ퟏ
ퟏퟎ
A. 10% of $1.00 is .1, or (10 cents). To find 10%, simply move the
decimal one place to the left.
To find 20% of a number, you could multiply a number by
The easier way, though, is to multiply a number by the decimal
form of 20%, which is....
To find 20% of any number, multiply by 2 and move the
decimal one place to the left.
ퟏ
ퟓ
B. 20% is what fraction?
ퟏ
ퟓ
.2
20% of 40 is….. 8

12. Mental Math:
Percent of a Number
Find 15% using mental math
Find 20% using mental math
1) 20
3)
42.1
1) 10
1) 10 3) 60 4) 120
3) 60
4) 380
Find 5% using mental math 1) 4) 160
10
3) 60
4) 125
2) 25
2) 20
2) 20
2) 3.5

13. Class Work: