newcommandddfrac[2]{frac{displaystyle #1}{displaystyle #2}}

newcommand{formdim}[2]
{
    begin{array}{l:c} % using arydshln for dashed vertical lines
        & text{footnotesize Dimensional Analysis} \ \
        begin{aligned}
            #1
        end{aligned} &
        begin{array}{c}
            #2
        end{array}
    end{array}
}

[
formdim{
    I &= ddfrac{mathcal{E}}{R_1} \
        &= ddfrac{-0.247}{0.28} \
        &= -0.8821428571; A
}{
    ddfrac{mathcal{E}}{R_1} = ddfrac{V}{Omega} \ \
    ddfrac{ddfrac{kg cdot m^1}{A cdot s^3}}{ddfrac{kg cdot m^2}{s^3 cdot A^2}} \ \
    ddfrac{kg cdot m^2 cdot s^3 cdot A^2}{A cdot s^3 cdot kg cdot m^2} \ \
    ddfrac{cancel{kg} cdot cancel{m^1} cdot cancel{s^3} cdot A^cancel{2}}{cancel{A} cdot cancel{s^3} cdot cancel{kg} cdot cancel{m^2}} = A \ \
    A
} % <------- Here is the pointing of the error
]