helping with math

this is a story from a newspaper subscribed by my son.i feel this is very interesting so.i put in my blog and wish the person who read it can have a good mood.

a primary school boy came home  and asked his father,"father ,this mathematics question is very difficult .can you help me,please?"the father come over and the son said ,"in this homework,the teacher said ,"suppose your father earns only one thousand dollars per month,and your mother spends about one thousand seven hundred dollars per month.so,what is the answer?"

the father said,"oh.this you have to go and ask your mother.she is the expert!"