The essence of futures is to sign long-term contracts with others to buy and sell goods (or stock indexes, foreign exchange, interest rates) in order to achieve the purpose of maintaining value or making money.

If you think the futures price will go up, go long (buy and open positions), go up (sell) and close positions, and earn: price difference = close positions-open positions.

If you think the futures price will fall, short (sell the position), fall (buy) and close the position, and earn: price difference = opening price-closing price.

Therefore, "opening a position" refers to signing a sales contract with others (deposit is required), "closing a position" refers to canceling the contract by cash settlement (deposit is returned and trading proceeds are settled), and "closing a position" refers to closing the position on the same day (generally, closing fees are exempted. )。

Buying quantity is the quantity of buying and selling futures.