Positive-negative

• 10 - (-3)
• 2 - (-7)
• 3 - (-10 )
• 7 - (-2)
• 9 - (-4)
• 4 - (-9)

You must build before you draw!!!

What is the rule for a positive - a negative? What is the justification?  

Class Ideas: 
* Add the two absolute values
*Why: Because you have to add zeros in order to take away negative
*Rewrite the problem into an addition problem.