Here, you can watch
a video on how to convert a number from another base system to the decimal system. So, you can see that converting back and
forth between counting systems only requires multiplying each digit of the number by its given base raised to the power
of its position in the number, then summing the result. The following applet includes an activity in geogebra for learning
to translate numbers from one base to another.
Original Geogebra Applet: Modulars and Bases