Polynomials from right to left
Let f,g and h be polynomials with nonzero constant term.
Write F, G and H for the polynomials you get by reversing the coefficients.
For example, if f=2x³+5x²3x+4 then F=4x³3x²+5x+2 (obtained by reading f from right to left).
Then fg=h if and only if FG=H.
This is a useful little trick, for example, when you need to determine whether a polynomial is irreducible.
