Задание
Перемножить числа:
| \(\displaystyle \times\) | \(\displaystyle 2\) | \(\displaystyle 5\) | |
| \(\displaystyle 3\) | \(\displaystyle 1\) | ||
| \(\displaystyle +\) | |||
Решение
1. Умножаем единицы числа \(\displaystyle 3\underline{1} \) (это цифра \(\displaystyle 1 \)) на число \(\displaystyle 25{\small : }\)
\(\displaystyle 1 \cdot 25=25 {\small . }\)
| \(\displaystyle \times\) | \(\displaystyle \bf 2\) | \(\displaystyle \bf 5\) | |
| \(\displaystyle 3\) | \(\displaystyle \bf 1\) | ||
| \(\displaystyle +\) | \(\displaystyle \bf 2\) | \(\displaystyle \bf 5\) | |
| \(\displaystyle ?\) | \(\displaystyle ?\) | ||
| \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) |
2. Умножаем десятки числа \(\displaystyle \underline{3}1\) (это цифра \(\displaystyle 3 \)) на число \(\displaystyle 25{\small : }\)
\(\displaystyle 3 \cdot 25=75 {\small . }\)
| \(\displaystyle \times\) | \(\displaystyle \bf 2\) | \(\displaystyle \bf 5\) | |
| \(\displaystyle \bf 3\) | \(\displaystyle 1\) | ||
| \(\displaystyle +\) | \(\displaystyle 2\) | \(\displaystyle 5\) | |
| \(\displaystyle \bf 7\) | \(\displaystyle \bf 5\) | ||
| \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) |
3. Складываем числа:
| \(\displaystyle +\) | \(\displaystyle 2\) | \(\displaystyle 5\) | |
| \(\displaystyle 7\) | \(\displaystyle 5\) | ||
| \(\displaystyle 7\) | \(\displaystyle 7\) | \(\displaystyle 5\) |
В итоге мы получаем:
| \(\displaystyle \times\) | \(\displaystyle 2\) | \(\displaystyle 5\) | |
| \(\displaystyle 3\) | \(\displaystyle 1\) | ||
| \(\displaystyle +\) | \(\displaystyle 2\) | \(\displaystyle 5\) | |
| \(\displaystyle 7\) | \(\displaystyle 5\) | ||
| \(\displaystyle 7\) | \(\displaystyle 7\) | \(\displaystyle 5\) |
Ответ: \(\displaystyle 775 {\small . }\)