What was the trick that the shopkeeper played to tempt people to play the game of luck?

The shopkeeper was very cunning and wanted everybody to try his luck. There were discs on the table with numbers. One person had to choose any six discs and find the total number of them. One had to pay him 50 paise for this. The person got the article marked with that number. Two people came to try their luck. An old man got a beautiful clock and he get ` 15 from the shopkeeper. Another boy who came, got four items. These people were the companions of the shopkeeper and helped him in playing tricks to tempt other people for trying their luck. This way, he used to tempt people.