[英语原文]Oneday,theteacherinquiredPeter：＂Howmuchisfourminusfour？＂Peterwastongue-tired.Theteachergotangryandsaid：＂Whatafool!Yousee,ifIputfourcoinsinyourpocket,butthereisaholeinyourpocketandallofthemleakout,nowwhatisleftinyourpocket？＂＂Thehole.＂repliedPeter.[汉语翻译]一天,老师问彼得：＂4减4等于几？＂彼得张口结舌答不上来。老师生气地说：＂真笨!你想,我要是往你口袋里放4个硬币,而你的口袋上有个窟窿,硬币全漏掉了,那么,你口袋里还剩下什么？＂＂窟窿。＂彼得答道。
