3 Title

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.

 *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.