Conversion

Hi guys, my first question here... !

this question might be an oldie... ive read a lot of posts on the internet trying to solve this... but still i couldnt find a real answer to my problem... here it goes:

i am trying to create a workbook/sheet in which i can list the costs of production for the company i am currently working at.

until here it is quite easy... just adding the costs, etc. BUT... this list must have two columns: one for reais (brazilian currency) and the other one for dollars.

until here it is quite easy to convert from reais to dollars... BUT my boss needs to edit both columns... because sometimes he has the costs in reais, other times in dollars..

i found a VBA script that would do this, but my boss uses a mac ...

(wouldnt life be easier if we could assign formulae to the column, instead of only the cell?)

do you have any insights ?

i am quite noob to excel, so please dont mock on me ! haha