5 months ago
Q:

115 times 9

Accepted Solution

A:

Solution variant #1.

Mutliply the bold numbers $5\times 9=45$
$\frac{\begin{matrix}\:\:&\:\:&4&\:\:\\\:\:&1&1&\bold{5}\\\times &\:\:&\:\:&\bold{9}\end{matrix}}{\begin{matrix}\:\:&\:\:&\:\:&5\end{matrix}}$
Add the carried number to the multiplication $4+1\times 9=13$
$\frac{\begin{matrix}\:\:&1&\bold{4}&\:\:\\\:\:&1&\bold{1}&5\\\times &\:\:&\:\:&\bold{9}\end{matrix}}{\begin{matrix}\:\:&\:\:&3&5\end{matrix}}$
Add the carried number to the multiplication $1+1\times 9=10$
$\frac{\begin{matrix}\:\:&1&\bold{1}&4&\:\:\\\:\:&\:\:&\bold{1}&1&5\\\times &\:\:&\:\:&\:\:&\bold{9}\end{matrix}}{\begin{matrix}\:\:&\:\:&0&3&5\end{matrix}}$
Add the carried digit, $1$, to the result
$\frac{\begin{matrix}\:\:&1&1&4&\:\:\\\:\:&\:\:&1&1&5\\\times &\:\:&\:\:&\:\:&9\end{matrix}}{\begin{matrix}\:\:&1&0&3&5\end{matrix}}$
Line up the numbers
$\begin{matrix}\:\:&1&1&5\\\times &\:\:&\:\:&9\end{matrix}$ $=1035$