Use mathematics and equations sparingly
It is not difficult to integrate equations into your talk if you keep
in mind a few simple precautions. First, make absolutely certain
that the equations are necessary, and if they’re not, toss them
out. Equations make a talk harder to understand, they slow the
pace, and they are prone to creating confusion. If overdone, they
also cause resentment; one literally will hear groans from an
audience when a speaker flashes an equation-filled transparency
on the screen. Audiences are especially scornful of speakers who load their presentations with equations because of a misguided
belief that the mathematics alone will imbue their work with a
more scientific or rigorous flavor.