Задание
Перемножить числа:
| \(\displaystyle 2\) | \(\displaystyle 5\) | ||
| \(\displaystyle \times\) | |||
| \(\displaystyle 3\) | \(\displaystyle 1\) | ||
| \(\displaystyle +\) | |||
Решение
1. Умножаем единицы числа \(\displaystyle 3\underline{1} \) (это цифра \(\displaystyle 1 \)) на число \(\displaystyle 25{\small:}\)
\(\displaystyle 1 \cdot 25=25 {\small.}\)
| \(\displaystyle \bf2\) | \(\displaystyle \bf5\) | ||
| \(\displaystyle \times\) | |||
| \(\displaystyle 3\) | \(\displaystyle \bf1\) | ||
| \(\displaystyle \bf2\) | \(\displaystyle \bf5\) | ||
| \(\displaystyle +\) | |||
| \(\displaystyle ?\) | \(\displaystyle ?\) | ||
| \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | |
2. Умножаем десятки числа \(\displaystyle \underline{3}1\) (это цифра \(\displaystyle 3 \)) на число \(\displaystyle 25{\small:}\)
\(\displaystyle 3 \cdot 25=75 {\small.}\)
| \(\displaystyle \bf2\) | \(\displaystyle \bf5\) | ||
| \(\displaystyle \times\) | |||
| \(\displaystyle \bf3\) | \(\displaystyle 1\) | ||
| \(\displaystyle 2\) | \(\displaystyle 5\) | ||
| \(\displaystyle +\) | |||
| \(\displaystyle \bf7\) | \(\displaystyle \bf5\) | ||
| \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | |
3. Складываем числа:
| \(\displaystyle 2\) | \(\displaystyle 5\) | ||
| \(\displaystyle +\) | |||
| \(\displaystyle 7\) | \(\displaystyle 5\) | ||
| \(\displaystyle \bf7\) | \(\displaystyle \bf7\) | \(\displaystyle \bf5\) | |
В итоге мы получаем:
| \(\displaystyle 2\) | \(\displaystyle 5\) | ||
| \(\displaystyle \times\) | |||
| \(\displaystyle 3\) | \(\displaystyle 1\) | ||
| \(\displaystyle 2\) | \(\displaystyle 5\) | ||
| \(\displaystyle +\) | |||
| \(\displaystyle 7\) | \(\displaystyle 5\) | ||
| \(\displaystyle 7\) | \(\displaystyle 7\) | \(\displaystyle 5\) | |
Ответ: \(\displaystyle 775{\small.} \)