83-[59-(22-18)]
22-18=4
59-4=55
83-55=28
$${\mathtt{83}}{\mathtt{\,-\,}}\left[{\mathtt{59}}{\mathtt{\,-\,}}\left({\mathtt{22}}{\mathtt{\,-\,}}{\mathtt{18}}\right)\right] = {\mathtt{28}}$$
83-[59-(22-18)]
22-18=4
59-4=55
83-55=28
$${\mathtt{83}}{\mathtt{\,-\,}}\left[{\mathtt{59}}{\mathtt{\,-\,}}\left({\mathtt{22}}{\mathtt{\,-\,}}{\mathtt{18}}\right)\right] = {\mathtt{28}}$$