Задание
Перемножить числа:
| \(\displaystyle 4\) | \(\displaystyle 3\) | \(\displaystyle 7\) | |||
| \(\displaystyle \times\) | |||||
| \(\displaystyle 7\) | \(\displaystyle 5\) | ||||
| \(\displaystyle +\) | |||||
Решение
1. Умножаем единицы числа \(\displaystyle 7\underline{5}\) (это цифра \(\displaystyle 5 \)) на число \(\displaystyle 437\):
\(\displaystyle 5 \cdot 437=2185 \).
| \(\displaystyle \bf4\) | \(\displaystyle \bf3\) | \(\displaystyle \bf7\) | |||
| \(\displaystyle \times\) | |||||
| \(\displaystyle 7\) | \(\displaystyle \bf5\) | ||||
| \(\displaystyle \bf2\) | \(\displaystyle \bf1\) | \(\displaystyle \bf8\) | \(\displaystyle \bf5\) | ||
| \(\displaystyle +\) | |||||
| \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | ||
| \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | |
2. Умножаем десятки числа \(\displaystyle \underline{7}5\) (это цифра \(\displaystyle 7 \)) на число \(\displaystyle 437\):
\(\displaystyle 7 \cdot 437=3059 \).
Записываем результат так, чтобы единицы \(\displaystyle 3059\) шли под той цифрой на которую мы умножали; в нашем случае это десятки числа \(\displaystyle \underline{7}5\) (то есть цифра \(\displaystyle 7 \)):
| \(\displaystyle \bf4\) | \(\displaystyle \bf3\) | \(\displaystyle \bf7\) | |||
| \(\displaystyle \times\) | |||||
| \(\displaystyle \bf7\) | \(\displaystyle 5\) | ||||
| \(\displaystyle 2\) | \(\displaystyle 1\) | \(\displaystyle 8\) | \(\displaystyle 5\) | ||
| \(\displaystyle +\) | |||||
| \(\displaystyle \bf3\) | \(\displaystyle \bf0\) | \(\displaystyle \bf5\) | \(\displaystyle \bf9\) | ||
| \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | \(\displaystyle ?\) | |
3. Складываем числа:
| \(\displaystyle 2\) | \(\displaystyle 1\) | \(\displaystyle 8\) | \(\displaystyle 5\) | ||
| \(\displaystyle +\) | |||||
| \(\displaystyle 3\) | \(\displaystyle 0\) | \(\displaystyle 5\) | \(\displaystyle 9\) | ||
| \(\displaystyle \bf3\) | \(\displaystyle \bf2\) | \(\displaystyle \bf7\) | \(\displaystyle \bf7\) | \(\displaystyle \bf5\) | |
В итоге получаем:
| \(\displaystyle 4\) | \(\displaystyle 3\) | \(\displaystyle 7\) | |||
| \(\displaystyle \times\) | |||||
| \(\displaystyle 7\) | \(\displaystyle 5\) | ||||
| \(\displaystyle 2\) | \(\displaystyle 1\) | \(\displaystyle 8\) | \(\displaystyle 5\) | ||
| \(\displaystyle +\) | |||||
| \(\displaystyle 3\) | \(\displaystyle 0\) | \(\displaystyle 5\) | \(\displaystyle 9\) | ||
| \(\displaystyle 3\) | \(\displaystyle 2\) | \(\displaystyle 7\) | \(\displaystyle 7\) | \(\displaystyle 5\) | |
Ответ: \(\displaystyle 32775\).