1) Create an account code in Chart of Account , in Less: Expenses
eg: 400-1200 Round Up/Down Expenses
2) Every month end, user are required to calculate the amount gain/loss and made an adjustment in GL -> Journal Entries
3) Go to General Ledger -> Journal Entries
select the Debit Account, eg : Cash In Hand, Bank
select 400-1200 Round Up/Down Expenses
3) depending on the situation, adjust using these 2 account codes.