Extracting Values in Excel

After reading the article on using excels right, left and mid string utility my life has been easier. However i am never happy as i have a series of alphanumeric entries in excel and i would like to know if thers is a formulae to take off the end *no. of characters.
e.g.
EXAMPLE(123)
EXAMPLE(234)
EXAMPLES(123)
using the left string function i can extract a certain number of figures from the left, however what would really be useful was if i could delete the last three characters of each cell.
I hope i managed to explain myself correctly and if anyone could help i would be greatful.