I think the idea is to learn how to do it the other way...

Sort of. Numerical Analysis for a CompSci was theoretical math (e.g. what is the Runge-Kutta method and how can it be correctly implemented on a digital computer). The idea is that a CompSci's role is to make the computer correctly and efficiently perform advanced math.

Numerical Analysis for an engineer was practical programming (e.g. when would I use the Runge-Kutta method and how can a computer help). The idea is that an Engineer's role is to apply the CompSci's work to the physical world.

Collaborating on homework with someone from the other discipline is an excellent opportunity. Shooting down Scud missiles and moon landings are the end result.