Mary and Jessi were in a market. They had to buy 4 apples, 3 oranges and 7 litchis. Mary told the shopkeeper their needs. The shopkeeper gave them 10 fruits in all. Jessi counted the fruits and said,"You have given us more fruits. We need only 9." "No, you have given us less. We need 18 fruits." Mary argued. "No, no. Both of you are wrong. You need a total of 14 fruits." the shopkeeper corrected. "But then if you knew the correct number of fruits we needed, then why did you give us 10 fruits?" asked Jessi irritated. " Because I wanted to teach you the importance of addition and subtraction in our daily lives." said the shopkeeper smiling.