[marcosdumay]

I like `qalc` a lot:

    > 5 pounds to kg
    5 * pound = approx. 2.2679619 kg

    > x^2 + 8*x = 4
    ((x^2) + (8 * x)) = 4 = approx. x = 0.47213595 or x = -8.472136

And so on.