Answer
Suppose a number\[abcd\]with 4 digits to the base \[e\] has place values.
\[{{e}^{3}},{{e}^{2}},{{e}^{1}},{{e}^{0}}\]
Multiply each digit in the numeral with place-value. Then, sum yields the numeral value in base ten.
That is.,
\[abc{{d}_{e}}=\left( a\times {{e}^{3}} \right)+\left( b\times {{e}^{2}} \right)+\left( c\times e \right)+\left( d\times 1 \right)\]
The number \[abcd\] is converted to base ten.
For example;
\[\begin{align}
& {{4327}_{six}}=\left( 4\times {{6}^{3}} \right)+\left( 3\times {{6}^{2}} \right)+\left( 2\times {{6}^{1}} \right)+\left( 7\times 1 \right) \\
& =991
\end{align}\]