简便验算

来源:百度知道 编辑:UC知道 时间:2024/06/10 22:12:20
119X39+39
=
=
345X101-345
=
=
(125+9)X8
=
=
341+13X31-131
=
=
420/[2X(201-194)]
=
=
139X27+3X139
=
=
(等于号随便用几个,但一定要是简便验算,我家,这是会家作业,以前学的,早忘了,急急急急急急急急急急急急急急急急急急急急急急急急急急急急急急!拜托了!!尽快)

119X39+39
=39(119+1)
=39×120
=4680
345X101-345
=345(101-1)
=345×100
=34500
(125+9)X8
= 125×8+9×8
= 1000+72
=1072
341+13X31-131
=341+403-131
=341-131+403
=210+403
=613
420/[2X(201-194)]
= 210/(201-94)
=210/107
139X27+3X139
=139(27+3)
= 139×30
=4170

这都不会