Count how many pairs of shoes?

Students always take note there is a god.
After class, the teacher asked her how, she said she wanted to buy a nice pair of new shoes, to find parents for money, I did not expect parents not to give her anger did not even eat rice came to the school.
Teacher thought for a moment, said: "I give you layout a homework, carefully count the home you and your parents' shoes, tell me the results tomorrow."
The next day, the teacher asked the students to see this: "Last night the number of shoes yet?"
She said: "counted."
The teacher asked: "How many pairs of shoes your father?"
The student said: "four pairs."
"Your mother?"
"6 pairs."
Teacher paused and asked: "How many pairs of shoes you have?"
Her face bright red, while to whispered: "12 pairs."
"Then you still angry?" At this time, the students eyes full of tears, her sobs, said: "Teacher, I was wrong. However, the teacher, you are not any been to my house, how do you know my parents' shoes No more than I do? "
Teacher lamented that: "Parents and children's shoes is always better than less, every household are the same, but do children often forget to count."