加加和减减

• 作 者: 褚晓蓉
• 出 处: 小朋友
• 发表日期: 2004年期
• 关键词: 三十六

乘法口诀有四十五句,同学们还在辛辛苦苦背诵的时候,玲玲却已经用口诀来做题目了!她的第一个诀窍是:“三句口诀一起记”,方法是“加一加”,“减一减”。比如,三七二十一,加一个七是四个七,二十一加七是二十八,四七二十八;减一个七是两个七,二十一减七是十四,二七十四。第二个诀

There are forty-five sentences of multiplication formulas, while the students are still hard to memorize, Lingling has already done the subject with her formulas! Her first trick is: “Remember the three formulas together” Plus “,” minus one minus ". For example, thirty-seven twenty-one, plus a seven is four seven, twenty-one plus seven is twenty-eight, four hundred twenty-seven; minus one seven is two seven, twenty-one minus seven is fourteen, two seventy four. The second tactic