Difference between 3B and tally

Anshuman Basu (account -GST) (1546 Points)

28 February 2020  
pl slove the problem
GSTR 2A - Rs 5000/- as IGST.
GSTR 3B - Rs 21000/- as IGST.
Our Books of Account- Rs 18000/- because we forgot to take purchase bill in my books of accounts and balance sheeet was finalized
sir which figure we mentioned in GSTR 9 and which column we put the data.
pl note all purchase bill in our hand. by mistake we not entry in our tally
what to do
pl help how I fill up GSTR 9?