Thank you for your suggestion Michael. Maybe I'll use a 4x4 keypad. I suppose the algorithm that I posted did not mention anything about buffers. I use buffers to keep the numbers though. Anyway, my question is if 12345 is stored in seperate buffers as in: |1|2|3|4|5|, where || is a memory location, how am I to convert it into a floating point number efficiently? My way is to multiply it: 1 x 10000 + 2 x 1000 etc. It takes up a lot of processing time. Is there a better way to convert it? Thanks.