Don't pad number strings, use modular arithmetic to calculate each digit

Example in Python:
// = integer division
% = remainder

# given t in tenths of seconds, 
# return a string of format string A:BC.D
# A = minutes, BC = seconds, with leading zero if needed, D = tenths of seconds
def format(t):
    tenths = t % 10
    t = t // 10
    sec = t % 60
    min = t // 60
    sec_ones = sec % 10
    sec_tens = sec // 10
    display = str(min) + ":" + str(sec_tens) + str(sec_ones) + "." + str(tenths)
    return display