The absolute value of a number is the positive magnitude to the number,
or, stated another way, if a number is positive (or zero), the absolute value of that number is the number itself; if a number is negative, the absolute value of that number is the negative of the negative number.
#abs(a) = {(a " if " a>= 0), (-a " if " a<0):}#
The absolute value of 98 is
#color(white)("XXXXX")#98.
The opposite of a number might mean one of two things:
#color(white)("XXXXX")#The additive inverse
#color(white)("XXXXX")##color(white)("XXXXX")#The number which when added to a given number equals 0.
#color(white)("XXXXX")##color(white)("XXXXX")#The **additive inverse of #98# is #(-98)#
#color(white)("XXXXX")#The multiplicative inverse
#color(white)("XXXXX")##color(white)("XXXXX")#The number which when multiplied by the given number equals 1.
#color(white)("XXXXX")##color(white)("XXXXX")#The multiplicative inverse of #98# is #1/98#.