+1090 $${{\mathtt{10}}}^{-{\mathtt{2}}} = {\frac{{\mathtt{1}}}{{\mathtt{100}}}} = {\mathtt{0.01}}$$
That's because you have to 1/10 * 1/10. When you do negative exponents, you are multiplying the number's recipricols. And 1/10 * 1/10 is the recipricol of ten multiplied by itself two times!
