I had to take a hell of a lot of calculus and physics, because I needed the background for thermodynamics (we called it "thermogoddammits") and quantum mechanics.

As for explosives, I would expect that the al Qaaqa explosives are being used in Iraq and possibly elsewhere in the world.  There was enough missing to supply bombers for decades.

And I'll remember your friend's place, as well as the code word!