Negative Numbers

Opposite numbers

Have opposite signs
Add up to zero

  Examples:  +3+-3=0    -3++3=0

Combining signs (more than one sign for the same number)

If even number of negative signs
Number is positive

  Examples:  ++3=+3   --3=+3   +(+3)=+3   -(-3)=+3   -(-(-(-3)))=+3   (-1)8=+1

If odd number of negative signs
Number is negative

  Examples:  +-3=-3   -+3=-3   +(-3)=-3   -(+3)=-3   -(-(-3))=-3   (-1)9=-1

Multiplying and Dividing signed numbers

Do the indicated operation

If even number of values with negative signs
Answer is positive

  Examples:  +3.+2=+6    -3.-2=+6    +6/+2=+3    -6/-2=+3    -2.-3.-5.-7=+210

If odd number of values with negative signs
Answer is negative

  Examples:  +3.-2=-6     -3.+2=-6     +6/-2=-3     -6/+2=-3     -2.-3.-5=-30

Adding or Subtracting two signed numbers

If same sign (both numbers have the same sign)
Add the numbers
Keep the sign

  Examples:  +3++2=+5     -3+-2=-5

If different signs (the numbers have different signs)
Subtract the numbers (put larger number on top)
Keep the sign of the larger (top) number

  Examples:  +3+-2=+1     -3++2=-1     +2+-3=-1     -2++3=+1

Last updated 6/2/97 - 8/31/2000.