You can use your fingers too. You have 2 fingers, and then you want 2 more, add the fingers and you have 4 fingers.
4 is the answer.
$${\mathtt{2}}{\mathtt{\,\small\textbf+\,}}{\mathtt{2}} = {\mathtt{4}}$$
.You can use your fingers too. You have 2 fingers, and then you want 2 more, add the fingers and you have 4 fingers.
4 is the answer.