You can include equations in your text, just write your equation and prepend $\tt{EQN:}$ to it.

The MathsMode page gives more details, but here are some simple examples:

 y=x^2 $y=x^2$ z(3)=y_0 $z(3)=y_0$ \int\frac{x^2}{2!}.dx $\int{x^2}.dx$ \int_0^\infty{e^{1/x}}dx $\int_0^\infty{e^{1/x}}dx$ e^x=\sum_0^\infty\frac{x^n}{n!} $e^x=\sum_0^\infty\frac{x^n}{n!}$

Yes, it takes practice, but it's easy once you get the knack.