499.99 divided by 20 %
$${\frac{{\mathtt{499.99}}}{{\mathtt{0.2}}}} = {\mathtt{2\,499.95}}$$
$${\mathtt{499.99}}{\mathtt{\,\times\,}}{\mathtt{0.2}} = {\mathtt{99.998}}$$ = 20% of 499.99 ∴
$${\frac{{\mathtt{499.99}}}{{\mathtt{99.998}}}} = {\mathtt{5}}$$