power to the base!

Numbers can be written in decomposed form. This applet allows you to explore the decomposition of integers into sums of multiples of powers of various bases. Is the decomposition of a given number unique? If yes, how do you know? If no, how many different decompositions can you find for a given number? Can you devise a way to write fractions between 0 and 1 in different number bases ? What problems could/would you set for your students based on this applet ?