To convert a number in base five to base ten, we shall use the expanded notation with the place value of each of the base five numbers.
The procedure is shown below;
[tex]\begin{gathered} 121_5 \\ \text{Assign place values starting from the right to the left} \\ \text{That is 0, 1 and 2.} \\ We\text{ now have}; \\ (1\times5^2)+(2\times5^1)+(1\times5^0) \end{gathered}[/tex]
We can now simplify this as follows;
[tex]\begin{gathered} (1\times25)+(2\times5)+(1\times1) \\ =25+10+1 \\ =36 \end{gathered}[/tex]
ANSWER:
[tex]121_5=36_{10}[/tex]
