Arithmetic Grade Six

Lesson Thirty-seven: Signed Addition

There are basically four combinations that you may have to deal with in signed computations: 


	1) positive + positive
	2) positive + negative
	3) negative + positive
	4) negative + negative
Your answer must be positive in the first situation. Your answer must be negative in the last situation. In situations two and three, your answer could be negative or positive depending on the numbers involved.

Situation Three: Positive Plus Negative
Your answer could be either positive or negative depending on which value is further from zero. 


	EXAMPLES:

	   32 + -17 =  15  
	(thirty-two is farther from zero than negative
	 seventeen and so the answer is positive)

	   17 + -32 = -15
	   40 + -60 = -20
	   60 + -40 =  20
Situation Four: Negative Plus Positive
Your answer could be either positive or negative depending on which value is further from zero. 

	EXAMPLES:

	  -32 + 17 = -15
	(negative thirty-two is farther from zero than 
	 seventeen and so the answer is negative)

	  -17 + 32 =  15
	  -60 + 40 = -20
	  -40 + 60 =  20

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