1.5  Subtraction of Real Numbers       Homework: Odds 17-93

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DSPM 0800 Class Notes

Examples of Additive Opposites:  8 and –8 are additive opposites. –9 and 9 are additive opposites. The sum of additive opposites is zero.

Use the Calculator to Compare Results For Each Line in the Two Columns:
-7-2                 -7 + (-2)                      Results: -9

4-9                   4 + (-9)                        Results: -5
-6-(-5)             -6 + (5)                        Results: -1

SUBTRACTION- Change to adding the opposite and use rules for addition.

Example:              Example:              
 Example:

_Example:

    

Example:        

Translate to Mathematical Language and Calculate:

Ex: The difference between 23 and –17.         Ex: Subtract –31 from –5.
                                                                       

Changes in Elevation:
To find the difference in elevation, subtract the lower elevation from the higher elevation (higher – lower).

Example: The lowest elevation in Asia, the Dead Sea, is 1312 ft. below sea level. The highest elevation in Asia, Mt. Everest, is 29,028 ft above sea level. Find the difference in elevation.

Remember: (higher – lower)