NO SIGN MEANS POSITIVE
• “ – ” means the number is negative
• “ + ” means the number is positive
•No sign usually means the number is really a positive number.
• Example 5 is really +5
Adding and Subtracting positive numbers is just simple addition and subtraction
Example: 2 + 3 = 5
is really saying
"Positive 2 plus Positive 3 equals Positive 5"
You could write it as (+2) + (+3) = (+5)
AND….
Example: 6 − 3 = 3
is really saying
"Positive 6 minus Positive 3 equals Positive 3"
You could write it as (+6) − (+3) = (+3)
Balloons and Weights
This basket has balloons and weights tied to it:
1)The balloons pull up (POSITVE)
2) And the weights drag down (NEGATIVE)
Here is what adding and subtracting positive numbers looks like
You can add balloons (you are adding positive value)
THE BASKET GETS PULLED UPWARDS (POSITIVE)
What if you add negative numbers?
You can add weights ( you are adding negative values The basket gets
pulled downwards (NEGATIVE)
What if you subtract negative numbers?
You take away weights (you are
subtracting negative values)
The basket gets pulled upwards
(POSITIVE)
So….
Subtracting a Negative made the basket GO UP!?!
So subtracting a Negative is the
same as Adding!!!!
Example
+ (+):3 + (+2) = 3 + 2 = 5
- ( - ): 6 – (-3) = 6 + 3 = 9
+ ( - ): 7 + (-2) = 7 – 2 = 5
- ( + ): 8 – (+2) = 8 – 2 = 6
So, all you have to remember is
•Two LIKE signs become a POSITVE sign
•Two UNLIKE signs become a NEGATIVE sign
LET’S WATCH A VIDEO
https://www.youtube.com/watch?v=lBscLuttQq0