inventory +/-

[lang]

sheet1 has a cell with list validation, a cell for user input, and a button.
sheet2 is hidden and has 2 columns of reference data. Example below:
item inv
nuts 100
bolts 20
washers 55
etc...
how should I code the button on sheet1 to update inv on sheet2?
ex: from sheet1 select bolts, enter 4, then click button to adjust bolts inv
on sheet2 from bolts 20 to bolts 16.

[nimrod]

Better description of problem and a downloaded example would really help here