There are two prices, one is low and the other is high. The low one is called bid (bank bid) and the high one is called ask (bank asking price).

You sell it to him, and his price is called an offer. He sells it to you, and the price he wants is the asking price.

Bid below the asking price. This is necessary, otherwise how can banks make money?

If the prices show 82.84 and 83.00, the price difference is 0. 16. You buy at this time, and your price is 83.00.

When can I make money? Wait until the price increase is greater than the spread, that is, the price shows 83.00 and 83. 16 or higher. At this point, if you choose to sell, you will get 83.00 yuan.