The clerk will not hand you the change in the Western way, adding up the coins and notes on top of the purchase price, starting with the small denominations. She will not say "7,150" and then put down a 50 yen coin saying "7,200", next putting down three 100 yen coins and saying "7,500", then a 500 yen coin saying "8,000", and finally two 1,000 yen notes saying "10,000" yen.
She will hand you all the different denominations in a lump, just saying: arigato-gozaimasu (thank you).
The method of giving change might appear most inconsiderate to those accustomed to the Western way. It might even arouse doubts as to whether one might have been short-changed.
But if you would carefully observe Japanese customers, you will note that most of them appear hardly to check the amount before putting it away.
It might be that some customers just trust the clerk or don't want to give the impression that they mistrust her. It might be that some feel that it's unseemly to count money in public.
In most cases, however, it's just that the Japanese are good and fast at arithmetic.
In the above example, the Japanese who pays for a 7,150 yen purchase with a 10,000 yen note has already calculated in his head the amount of change he should receive. When the change is handed to him, one swift glance and quick mental arithmetic tells him whether it is the correct amount.
Conversely, a Japanese travelling in the United States for the first time is usually bewildered when the clerk hands him change in the Western way. He would think that it is a lot of unnecessary trouble and excessive consideration for the customer.