1. Objective- To simplify problems involving subtraction of real numbers and percents.
Algebraic Definition of Subtraction
a - b = a + -b
Evaluate if x = 4.5 and y = - 3.7
1) x - y =
2) y - x =
4.5 - ( ) = =
8.2
( 4.5 ) =
- 8.2

2. Simplify. 1) - 10 - ( - y ) = 2) 5x + 3y - 2 - x =
3) 5x - y - 3(x - y) =

3. Simplify. - 10 + y = y - 10 1) - 10 - ( - y ) = 2) 5x + 3y - 2 - x =
3) 5x - y - 3(x - y) =
5x - y - 3x + 3y
2x + 2y

4. Geometric Model for Subtraction5 x 12
x =
x = 7

5. Percent Discount Sweater = $85
Find the new price after a 20% discount.
Long Way
Shortcut
original price - discount
new price
$ % of $85
(100% - 20%) of $85
( 85)
80% of $85
.80 (85)
$68
$68
( Subtracts the $ )
( Subtracts the % )

6. Find the new price. .80P 1) Price P is discounted 20%. .65Y
2) Price Y is discounted 35%.
.65Y
3) Price M is discounted 47%.
.53M
.835J
4) Price J is discounted 16.5%.

7. Find the new price. 1.12X 1) Price X is marked up 12%. 1.70L
2) Price L is increased 70%.
1.70L
3) Price P is marked up 16%.
1.16P
1.0825K
4) Price K after sales tax of 8.25%.

8. Range- Difference between the highest value and lowest value in a set of numbers.
Temperatures in Alaska last night :
Range = High - Low
Range =
Range =

9. Find the range. 1) High Test Score = 94 Low Test Score = 68
2) High Temp. =
Low Temp. =