Incidentally, we used the parentheses, () in b^( − 1) for clarity, but ordinarily the symbol is written simply as b^− 1, and we will follow this usage from now on.

So here we have reached something new, a negative exponent. Now let’s see if we can find out what this negative exponent means by the same method we used to investigate an exponent of 0. We have just shown , by our division rule, that and we can write b² = b × b, and b³ = b × b × b, so we have