I know...😉
$${\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{10}} = {\mathtt{19}}$$
$${\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{10}} = {\mathtt{19}}$$
.$${\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{10}} = {\mathtt{21}}$$
.$${\mathtt{a}}{\mathtt{\,\small\textbf+\,}}{\mathtt{b}} = {\mathtt{c}}$$
$$\Rightarrow 9+10=19$$
.I know...😉
$${\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{10}} = {\mathtt{19}}$$