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Теория: Умножение двузначных чисел

Задание

Перемножить числа:

   \(\displaystyle 7\)\(\displaystyle 2\)
  \(\displaystyle \times\)  
   \(\displaystyle 3\)\(\displaystyle 6\)
 
  
\(\displaystyle +\)    
  
 
 

 

Решение

1. Умножаем единицы числа \(\displaystyle 3\underline{6} \) (это цифра \(\displaystyle 6\)) на число \(\displaystyle 72{\small:}\)

 

\(\displaystyle 6 \cdot 72=432\) (здесь также можно использовать умножение в столбик).

 

   \(\displaystyle \bf7\)\(\displaystyle \bf2\)
  \(\displaystyle \times\)  
   \(\displaystyle 3\)\(\displaystyle \bf6\)
 
  \(\displaystyle \bf4\)\(\displaystyle \bf3\)\(\displaystyle \bf2\)
\(\displaystyle +\)    
 \(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\) 
 
 \(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)

 

2. Умножаем десятки числа \(\displaystyle \underline{3}6\) (это цифра \(\displaystyle 3\)) на число \(\displaystyle 72{\small:}\)

 

\(\displaystyle 3 \cdot 72=216{\small.} \)

 

   \(\displaystyle \bf7\)\(\displaystyle \bf2\)
  \(\displaystyle \times\)  
   \(\displaystyle \bf3\)\(\displaystyle 6\)
 
  \(\displaystyle 4\)\(\displaystyle 3\)\(\displaystyle 2\)
\(\displaystyle +\)    
 \(\displaystyle \bf2\)\(\displaystyle \bf1\)\(\displaystyle \bf6\) 
 
 \(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)\(\displaystyle ?\)

 

3. Складываем числа:

  \(\displaystyle 4\)\(\displaystyle 3\)\(\displaystyle 2\)
\(\displaystyle +\)    
 \(\displaystyle 2\)\(\displaystyle 1\)\(\displaystyle 6\) 
 
 \(\displaystyle \bf2\)\(\displaystyle \bf5\)\(\displaystyle \bf9\)\(\displaystyle \bf2\)

 

В итоге мы получаем:

   \(\displaystyle 7\)\(\displaystyle 2\)
  \(\displaystyle \times\)  
   \(\displaystyle 3\)\(\displaystyle 6\)
 
  \(\displaystyle 4\)\(\displaystyle 3\)\(\displaystyle 2\)
\(\displaystyle +\)    
 \(\displaystyle 2\)\(\displaystyle 1\)\(\displaystyle 6\) 
 
 \(\displaystyle 2\)\(\displaystyle 5\)\(\displaystyle 9\)\(\displaystyle 2\)

Ответ: \(\displaystyle 2592 {\small.}\)