The example you cited did not generate exchange gains or losses. The condition of exchange gains and losses is that there is still a foreign currency balance in the bank deposit or current account at the end of the month, and exchange gains and losses need to be adjusted. In this example, there is no current account, and bank deposits are converted and received at the real-time exchange rate, so there is no exchange gain or loss.

Suppose that when you buy goods, you agree with the supplier to pay one month later, instead of paying at that time, and you need to settle foreign exchange after one month, then exchange gains and losses will occur:

Borrow: Goods in stock 100

Loan: accounts payable 100

Assuming that the exchange rate at the time of payment is 1 USD =9 yuan RMB, or payment is not made until the end of the month, and the exchange rate at the end of the month is 1 USD =9 yuan RMB, there will be exchange gains and losses:

Debit: financial expenses-1010 * (9-10)

Loan: accounts payable-10