How can we count in base eleven? We work in base 10. We know base 3 would count 1, 2, 10, 11, 12, 20. How would we count in base 11?
You would have to add a symbol for $10$, such as $A$. Then it would be
$$\begin{array}{|c|c|c|c|c|c|c|}
\hline 
\text{Base 10} &amp; 1 &amp; 2 &amp; 3 &amp; \dots &amp; 9 &amp; 10 &amp; 11 \\ \hline
\text{Base 11} &amp; 1 &amp; 2 &amp; 3 &amp; \dots &amp; 9 &amp; A &amp; 10 \\ \hline
\end{array}$$
You know how counting in Hexadecimal is done right? It could be done similarly with just the A included.Leave out the other alphabets.