resistors do resistor stuff. resistors in series Their resistance add!
\begin{equation} R_{eq} = R_1 + R_2 + \dots \end{equation}
CURRENT remains the same through the resistors. resistors in parallel Their resistance add by inverse fraction!
\begin{equation} \frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \dots \end{equation}
VOLTAGE remains the same through the resistors.