四年级简便计算:645+299-(645-198)
来源:学生作业帮助网 编辑:作业帮 时间:2024/09/08 19:04:32
![四年级简便计算:645+299-(645-198)](/uploads/image/z/2991330-18-0.jpg?t=%E5%9B%9B%E5%B9%B4%E7%BA%A7%E7%AE%80%E4%BE%BF%E8%AE%A1%E7%AE%97%EF%BC%9A645%2B299-%EF%BC%88645-198%EF%BC%89)
x){:{ӝ[Z|]Ó}_[|{fjYZdZZiTO;lX|ʊ'<]餞'?t_7XDlAf@am#/.H̳!ۉp7p9xmF3b]C]#bxmc%PIp-ML@& PM@J& wBL#9
g!8@`ˁ5$xD)t, .
四年级简便计算:645+299-(645-198)
四年级简便计算:645+299-(645-198)
四年级简便计算:645+299-(645-198)
利用交换率和结合律
645+299-645+198
=645-645+198+2+297
=0+200+297
=497
497
645+299-(645-198)
=645-645+299+198
=299+198
=300+198-1
=497
645-645+299+198=300+200-1-2=497
645-645+299+198=497
645+299-(645-198)
=645+300-1-(645-200+2)
=944-(445+2)
=944-445-2
=944-444-1-2
=500-3-1-2
=497
645+299-(645-198)
=645+299-645+198
=645-645+299+198
=300-1+200-2
=500-3
=497
645+299-(645-198)
=645+299-645+198
=645-645+299+198
=0+(300-1)+(200-2)
=300-1+200-2
=300+200-1-2
=500-1-2
=499-2
=497