+33665 Just type it directly into any scientific calculator as you have written it.
If you do it without a calculator, remember that you do what's in the brackets first, then do any multiplications and divisions, then any additions and subtractions.
$${\mathtt{10}}{\mathtt{\,\times\,}}{\mathtt{20}}{\mathtt{\,-\,}}\left({\frac{{\mathtt{20}}}{{\mathtt{10}}}}\right){\mathtt{\,\small\textbf+\,}}{\mathtt{21}} = {\mathtt{219}}$$
