Beginning Algebra
Answer/Discussion to Practice Problems
Tutorial 5: Adding Real Numbers
Answer/Discussion
to 1a
15 + 7 
15 + 7 = 8
The difference between 15 and 7 is 8 and the sign of 15 (the larger
absolute value) is , that is how we get the answer of 8. 
Answer/Discussion
to 1b


*Mult. top and bottom of first fraction by 2 to get the LCD of 10
*Add the numerators and write over common denominator 10

The sum of the absolute values would be 13/10 and their common sign
is , that is how we get the answer of 13/10. 
Answer/Discussion
to 1c
3.2 + (1.3) + ( 4.1) 

*3.2 + (1.3) = 1.9
*1.9 + (4.1) = 2.2

Answer/Discussion
to 1d
 4 + (3) + 2 

* 4 + (3) = 7
*  7 + 2 = 5
*Evaluate the absolute value 
Answer/Discussion
to 2a
1/2 
The opposite of 1/2 is 1/2, because both of these numbers have
the same absolute value, but are on opposite sides of the origin on the
number line. 
Answer/Discussion
to 2b
20 
The opposite of 20 is 20, because both of these numbers have
the same absolute value, but are on opposite sides of the origin on the
number line. 
Answer/Discussion
to 3a
( 4) 
Since the opposite of a negative is a positive, our answer is 4. 
Answer/Discussion
to 3b


*Evaluate the absolute value

Last revised on July 24, 2011 by Kim Seward.
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