[tex] {a}^{ - m} = \frac{1}{ {a}^{m} } [/tex]
[tex](a {}^{m} ) {}^{n} = {a}^{ mn} [/tex]
[tex] {a}^{m} \times {a}^{n} = {a}^{m + n} [/tex]
[tex] {a}^{m} \div {a}^{n} = {a}^{m - n} [/tex]