张颖宁波:急寻简算高手

来源:百度文库 编辑:杭州交通信息网 时间:2024/05/09 11:57:08
一、简算:
(1)2005+2006*20052005-2005*20062006+1
(2)55*53/54+26*26/27
(3)21+29/47*28+19/47*29

2005+2006*20052005-2005*20062006+1
= 2005 + 2006*2005*10001 - 2005*2006*10001 + 1
= 2006

55*53/54 + 26*26/27
= (55*53+26*52)/54
= (55*53+26*53-26)/54
= (81*53-26)/54
= 4267/54

21+29/47*28+19/47*29
= 21 + (28*29+19*29)/47
= 21 + 47*29/47
= 21 + 29
= 50