I have a table with columns:
item,qty,unit1,ratio,unit2

the qty here are referring to qty in unit1
for the same item, the ratio and unit2 are always the same

I then have a pivot table with:
item,unit1,sum of qty

I would like to add calculated field (qty2) where
qty2=quotient(sum of qty,ratio)
qty3=mod(sum of qty,ratio)

how to do it?
thanks.