


Signed NumbersMultiplicationis twice as far to the left of the origin as 1.
Thus, . Similarly, is twice as far to the left of the origin as 5.
Thus, . In general, for any two numbers a and b, we have . We say "a positive times a negative is negative". By the commutative law:
and in general
So we say "a negative times a positive is negative". Using the properties and we obtain (a)(b) = ab So we say "a negative times a negative is positive". The following table of signs is useful in remembering these rules:
Example 3.Look at some examples of multiplying negative numbers below: Here are some further examples of multiplying three numbers: Exercise 4.Try multiplying some negative numbers yourself. Got that down? Then try these harder exercises: << Subtraction  Signed Numbers Index  Division >>
