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简便计算8.59+2.57+3.43+5.47;      

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/21 07:14:07
简便计算
8.59+2.57+3.43+5.47;                 
301×79;
125×72×8;        
1280÷16÷8.
(1)8.59+2.57+3.43+5.47
=(8.59+5.47)+(2.57+3.43)
=14.06+6
=20.06                
(2)301×79
=(300+1)×79
=300×79+79
=23700+79
=23779
(3)125×72×8
=125×8×72
=1000×72
=72000   
(4)1280÷16÷8
=1280÷(16×8)
=1280÷128
=10