I have a checkbox linked to cell A1. In the cell B1 I have a number which
could be (say) 1 or 2. When the checkbox is "unchecked" and therefore A1 =
FALSE I want to clear the contents of B1. I can't do it by a formula in B1
because the number has been entered manually.

The best way I can think of is to run a macro when checkbox is clicked, and
if A1 = FALSE then clearcontents of B1, but how do I refer to the linked cell
for the particular checkbox in the macro? This same macro would be run for up
to 50 checkboxes all in column "A" so I could just refer to the cell by
Cell("A" & rownum).Offset(0, 1) but how do I find out what 'rownum' is for
the checkbox that has been clicked please?

Regards, Brett