How do you find the sum of numbers with different signs
Subtract and take the sign of the bigger number
400
-27 - (-3)
-24
400
Subtracting a negative is the same thing as...
Adding a positive
400
It will be – 12º tonight. The weatherman predicts it will be 25º warmer
by noon tomorrow. What will the temperature be by noon tomorrow?
What is 13 degrees
500
Two numbers whose sum equals zero
Additive Inverse
500
-16+18+-17
-15
500
-10 - 11 - (-3)
-18
500
-10 + (-2) - 5
-17
500
Which situation can be represented by the expression -30+30
a. Diana adds 30 mL of water to a test tube containing 30 ML
b. Mary owes the phone company $30 and pays $10
c. Deante did fewer sit ups than than the night before. He does 30 sit ups tonight
d. A diver is 30 ft below the surface of the water and then comes up to the surface