Balance sheet with approx amount or exact amount

I don't have all the invoices for all my assets like gold, car etc. But I do remember the approax amount. Can I prepare the Balance sheet with approax amount or should I prepare the balance sheet with exact amount. There might a slight variation of Total Net amount like plus or minus approax 10 to 20 thousands. In short, what happens when you don't have Bills or Invoice with you and you need to prepare the Balance Sheet and you want to show all details for income tax