Download Additive Inverses

2-3 Addition of Rational Numbers(pgs 63-70)
2-4 Subtraction of Rational Numbers (pgs71-76)
Assignment
2-3/68-69/3-63 M3
2-4/74-75/3-54M3
Vocab
Additive Inverses (2-3)
• Two rational numbers with a sum of_______.
1
1
(examples: -4.2 and 4.2 ,
and 
2
2
Note:
1

2
1
2
1
2
All represent the same quantity
)
Think of the number line for adding
integers
• Add a positive integer by moving to the
___________on the number line
• Add a negative integer by moving to the
________ on the number line
• Subtract an integer by adding its opposite
Rules for Addition of Integers
1)To add integers having the ___________sign, _________ the
absolute value of each number. __________the same sign.
(SAK)
Same-Add-Keep
2) To add integers with ____________signs, _____________the
smallest absolute value from the largest. Use the sign of the
number with the ________________absolute value and. (DSL)
Different-Subtract- Larger
3) Subtract an integer by ____________________its opposite.
(then follow 1 or 2)
4) Watch out! The negative of a negative is the opposite positive
number.
-(-a) = +a
Examples
• Find the additive inverse
1) 5.7
2)
3) –(-6)
6

5
Add or Subtract
(For HW you must show finding common denominator for all fractions)
4) -10 + -15
5)
-3 – 8
(SAK or DSL?)
(change then SAK or DSL)
6) (-5) + 4 +(-12) + 13 (Hint: Combine + and – first)
7)
8)
4 2

5 5
1  2

6
9
9) -50 – 3
10)
1 1

12 3
11) -2 –(-5x) + 8x – 3x – (-6)
12) Joe has $86 in his account and writes a check for $95.
How much is in his account?
13) It was 12°F at 6:00 pm at midnight it was -3°F, how
much did the temperature change?