Depends on what business you do. If you are selling small businesses and there are many people, such as selling vegetables, it is obviously unrealistic for you to count the counter for half a day. When you finish counting, it is estimated that no one will buy it.

If it is a snack bar, if there are many people, you can't count the number of counters.

If you are doing big business, such as diamonds, it doesn't matter much.

Generally speaking, if it's a small matter, just practice oral calculation more.

These should be easy to overcome, and you can do it yourself.