Сумма чисел 72 и 18 равна: 90, 86, 96, 100.
72 + 18 = 90
$\begin{array}{r}\begin{array}{r}+\end{array}\underline{\begin{array}{r}72\\ 18\end{array}}\\ \begin{array}{r}90\end{array}\end{array}$
Разность чисел 52 и 25 равна: 37, 25, 27, 30.
52 − 25 = 27
$\begin{array}{r}\begin{array}{r}-\end{array}\underline{\begin{array}{r}52\\ 25\end{array}}\\ \begin{array}{r}27\end{array}\end{array}$