Hello, 4 different letters and 3 different digits X represent a letter - represent a digit All letters must be kept together: 4 possiblities XXXX--- -XXXX-- --XXXX- ---XXXX
There are 26 letters. For each possiblity: 26 choices for the 1 letter 25 choices for the 2 letter 24 choices for the 3 letter 23 choices for the 4 letter
There are 10 digits: 10 choices for the 1 digit 9 choices for the 2 digit 8 choices for the 3 digit
Numbers of codes: 4*26*25*24*23*10*9*8=1033344000.
