10^18   exa     E
10^15   pecta   P
10^12   tera    T
10^9    giga    G
10^6    mega    M
10^3    kilo    k
10^2    hecto   h
10      deca    da
10^-1   deci    d
10^-2   centi   c
10^-3   milli   m
10^-6   micro   (greek mu) sometimes letter u is used in computer texts
10^-9   nano    n
10^-12  pico    p
10^-15  femto   f
10^-18  atto    a