Download Adding and Subtracting Positive and Negative Numbers 6.3

Adding and Subtracting Positive
and Negative Numbers
Addition
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Negative + Negative = a “greater” negative
Add the numbers
Include a “-” sign
Examples:
-6 + -4 = -10
-2 + -2 = -4
• Practice
-3 + -8 =
-12 +-10 =
Addition Continued
• Positive + Positive = a greater positive number
– Duh!! You’ve known this forever
• Example:
2+2=4
• Let’s move on!
Addition Continued
• Positive + Negative (or Negative + Positive)
• Follow these rules:
– Find the difference of the two numbers
– Use the larger number’s sign
• Example:
-23+4 =
Find the difference: 23 – 4 = 19
Larger number’s sign is negative
So, -23+4 = -19
• Practice:
49 + (-23)=
-94 +87 =
Subtraction
• Change the problem to an addition problem
• Keep the first number the same, change the second
number to its opposite (OPP)
• Then follow the rules of addition:
– Find the difference of the two numbers
– Use the larger number’s sign
• Example:
32-68 = change to 32 + (-68) =
32 + (-68) =
Find the difference: 68-32 = 36
Use larger number’s sign = -36
Subtraction Continued
• Your turn. Complete these problems. Show
your work!!
23 – 49 =
-25 – 35 =
22 - 45 =