Download Adding Real Numbers

Adding Real Numbers
One for you , two for me…..
What does closure mean?
Add 2+ 3. What answer do you get?
Add 12 + 24. What answer do you
get?
When you add any two real numbers,
how many answers do you get?
This is the meaning of the closure property of addition.
How do I add using a number
line?
Add 6 + (-5)
First mark 6 on the number line
Then move 5 spaces in the
OPPOSITE direction!
What is your answer?
Now you try
-2 + 5
3 + (-6)
But what if I don’t want to use a
number line?
1.
2.
3.
4.
Isolate your quantities
Combine your positive terms
Combine your negative terms
Think MONEY!!!!!!!!!!! (Positive numbers are
what you have in your pocket, negative numbers are
what you owe)
3 + 4 + (-5) + (-3) + 12 + (-2)
How does the associative
property help?
2 + ( -2 + 5)
Think associations
(2 + -2) +5
2 and –2 are additive inverses so their sum is 0
What is left? 5!!!!!!!
Give examples of properties
Commutative Property:
a+b = b+a.
Inverse Property of Addition:
a + -a = 0
Identity Property of Addition: a+ 0 = a
Now you do these with numbers!
Real Life Application
A company has a profit if the income
(receipts) is more than the expenses
(costs). But if the expenses are more,
the company has a loss.
Profits are denoted with positive numbers and losses
are shown using negative numbers
So let’s try
In January, my business lost $13143 and in
February, I lost another $6783. In March, I lost
$4735. But business picked up in April through
June with profits of $3825, $7613, and $12933
Please help me find out if I have an overall profit
or loss!
Now it is YOUR TURN!
Section 2.3 in the practice workbook
DON’T FORGET!!!!
Quiz 9/8 covers sections 2.1- 2.3
Vocabulary Due September 15
Tutoring Tuesday through Friday
mornings at 8:15 AM