Math CentralQuandaries & Queries


Question from Nick, a student:

Thanks Penny, again,
now i have another question. This is how i solved it and i know its suppose to be a negative.

z= |-3|-|-4|

so i clear the brackets

z= -3+4

and add the rest to get what z equals to


but i know it should be negative i just don't know what I'm doing wrong


The vertical line segments on each side of a number are not brackets, they indicate the absolute value of the number.

The absolute value of a number is one of two things. If the number is not negative then the absolute value of the number is itself. Thus the absolute value of 6, written |6|, is 6, |1/3| is 1/3 and |0| is 0. If the number is negative then to find the absolute value you just drop the negative sign. Thus |-2| is 2 and |-1/7| is 1/7.


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