Thinking Mathematically (6th Edition)

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}