a = 1
b = 2
a + b

# output

3

\[\begin{aligned} \nabla\cdot\mathbf{E} &= 4 \pi \rho \\ \nabla\cdot\mathbf{B} &= 0 \\ \nabla\times\mathbf{E} &= - \frac{1}{c} \frac{\partial\mathbf{B}}{\partial t} \\ \nabla\times\mathbf{B} &= - \frac{1}{c} \left(4 \pi \mathbf{J} + \frac{\partial\mathbf{E}}{\partial t} \right) \end{aligned}\]

julia> a = 1
1

julia> b = 2;

julia> c = 3;  # comment

julia> a + b + c
6