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EQ: How is mathematics helpful in search and rescue operations?
|Signed numbers let us show directions. It often helps us indicate above or below a certain reference point. For example, below zero degrees on a thermometer is indicated by a negative number and below sea level is also indicated by a negative number.|
Adding Signed Numbers
|If the signs are the same:
Step 1: Add the numbers.
Step 2: The answer will have the original sign.
+3 + +7 = +10
-3 + -7 = -10
|If the signs are different:
Step 1: Subtract the smaller absolute value from the larger absolute value.
Step 2: The answer will have the sign of the larger number.
+3 + -7 = -4 (7-3=4) the sign of the larger value is negative so the answer is -4
-3 + +7 = +4 (7-3=4) the sign of the larger value is positive so the answer is+4
It does not matter which number is listed first!
Go to next page for Subtracting Signed Numbers