Question 70622
The answer is -20 because the when you take the absolute value of any number becomes a 
positive number.  In this problem taking the absolute value of -20 makes it + 20, and that
is the largest number in the set.
.
{{{abs(4) = 4}}}
.
{{{abs(-1) = -(-1) = +1}}}
.
{{{abs(12) = 12}}}
.
{{{abs(-20) = -(-20) = +20}}}
.
{{{abs(19) = 19}}}
.
{{{abs(0) = 0}}}
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Another way to look at this is that when you take the absolute value of a number you are finding
the distance that number is from zero on the number line.  The absolute value of -5 is the 
same as the absolute value of +5 because both numbers are 5 units away from 0 on the number 
line.  In your problem -20 is 20 units from zero on the number line.
.
And another way to look at it is to just convert all the numbers to positive values and
then choose the largest of these values as the answer to your problem.
.
Hope this helps you to visualize what the absolute value means regarding numbers. It
just leaves positive numbers as positive, and it converts negative numbers to positive
numbers.