@Pikoh

Challenge 2 - Hidden numbers
The Nazi air force is trying to transmit numbers (maybe representing army units or available stock) over the radio and the Enigma code has just been broken, so they try to find out a pen and paper solution to send those numbers in a sort of secret manner. They decide to encode them on an arbitrary base using arbitrary symbols to represent the number. The good thing is that we only care about the order of magnitude of such numbers and their minimum and maximum possible values.