You can't physically sub-divide a column, but you can split data out
into separate columns. For example, if you have codes in column A made
up of 3 letters followed by 4 numbers, then these formulae copied down
the columns will extract the letters into column B and the numbers
into column C:
B1: =LEFT(A1,3)
C1: =RIGHT(A1,4)*1
Hope this helps.
Pete