One day, the teacher inquired Peter: "How much is four minus four?" Peter was tongue-tired. The teacher got angry and said: "What a fool! You see, if I put four coins in your pocket, but there is a hole in your pocket and all of them leak out, now what is left in your pocket?" "The hole," replied Peter.
一天,老師問(wèn)彼得:“4減4等于幾?”彼得張口結(jié)舌答不上來(lái)。老師生氣地說(shuō):“真笨!你想,我要是往你口袋里放四個(gè)硬幣,而你的口袋上有個(gè)窟窿,硬幣全漏掉了,那么,你衣袋里還剩下什么?”“窟窿。”彼得答道。