A (method of [[Quadrature|Numerical Integration]] for solving [[Differential Equations]]. For each iteration $z_i$, $ \huge \begin{align} k_{1}&= f(t_{i},z_{i}) \\ k_{2} &= f\pa{ t_{i} + \frac{2}{3}h, z_{i}+\frac{2}{3}hk_{1} }\\ \hline z_{i+1} &= z_{i} + h \pa{ \frac{1}{4}k_{1} + \frac{3}{4}k_{2} } \end{align} $