Android: Generate audio file containing random numbers to be played through earspeaker

I'm working on a project where I'm trying to play randomly generated numbers through the ear speaker, then ask the user to enter the numbers played through the keypad and figure out whether they match or not.

I stumbled across a few questions on this site regarding generating random numbers, but I'm lacking the basic information needed in order to proceed with my task. My question can be broken into the following:

• How can I generate random numbers in an audio file?
• How can I play the sound through the ear speaker? It seems this might be the answer.
• How can I match/compare user input with what the audio file played (numbers)?