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Теория: Умножение двузначных чисел

Задание

Перемножить числа:

  \(\displaystyle \times\)\(\displaystyle 7\)\(\displaystyle 6\)
 \(\displaystyle 6\)\(\displaystyle 9\)
\(\displaystyle +\) 
 
 

 

Решение

1. Умножаем единицы числа \(\displaystyle 6\underline{9} \) (это цифра \(\displaystyle 9\)) на число \(\displaystyle 76{\small : }\)

 

\(\displaystyle 9\cdot 76=684{\small . }\)

 

  \(\displaystyle \times\)\(\displaystyle \bf 7\)\(\displaystyle \bf 6\)
 \(\displaystyle 6\)\(\displaystyle \bf 9\)
\(\displaystyle +\) \(\displaystyle \bf 6\)\(\displaystyle \bf 8\)\(\displaystyle \bf 4\)
\(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\) 
 \(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)

 

2. Умножаем десятки числа \(\displaystyle \underline{6}9\) (это цифра \(\displaystyle 6\)) на число \(\displaystyle 76{\small : }\)

 

\(\displaystyle 6\cdot 76=456{\small . }\)

 

  \(\displaystyle \times\)\(\displaystyle \bf 7\)\(\displaystyle \bf 6\)
 \(\displaystyle \bf 6\)\(\displaystyle 9\)
\(\displaystyle +\) \(\displaystyle 6\)\(\displaystyle 8\)\(\displaystyle 4\)
\(\displaystyle \bf 4\)\(\displaystyle \bf 5\)\(\displaystyle \bf 6\) 
 \(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)

 

3. Складываем числа:

\(\displaystyle +\) \(\displaystyle 6\)\(\displaystyle 8\)\(\displaystyle 4\)
\(\displaystyle 4\)\(\displaystyle 5\)\(\displaystyle 6\)  
 \(\displaystyle 5\)\(\displaystyle 2\)\(\displaystyle 4\)\(\displaystyle 4\)

 

В итоге мы получаем:

  \(\displaystyle \times\)\(\displaystyle 7\)\(\displaystyle 6\)
 \(\displaystyle 6\)\(\displaystyle 9\)
\(\displaystyle +\) \(\displaystyle 6\)\(\displaystyle 8\)\(\displaystyle 4\)
\(\displaystyle 4\)\(\displaystyle 5\)\(\displaystyle 6\) 
 \(\displaystyle 5\)\(\displaystyle 2\)\(\displaystyle 4\)\(\displaystyle 4\)

Ответ: \(\displaystyle 5244{\small . }\)