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(1)1.25*6.4*7(2)9.9*7.8+0.78(3)0.77/0.55(4)7.5*1.02(5)3.7*2.

来源:学生作业帮 编辑:神马作文网作业帮 分类:数学作业 时间:2024/11/13 13:44:50
(1)1.25*6.4*7(2)9.9*7.8+0.78(3)0.77/0.55(4)7.5*1.02(5)3.7*2.8+12.5的简便计算.
(1)1.25*6.4*7(2)9.9*7.8+0.78(3)0.77/0.55(4)7.5*1.02(5)3.7*2.
(1)1.25*6.4*7
=1.25*0.8*8*7
=1*56
=56
(2)9.9*7.8+0.78
=99*0.78+0.78
=0.78*(99+1)
=78
(3)0.77/0.55
=0.11*7/0.11*5
=7/5
(4)7.5*1.02
=7.5*(1+0.02)
=7.5+7.5*0.02
=7.2+0.15
=7.35
(5)3.7*2.8+12.5
=3.7*(3-0.2)+12.5
=11.1-0.74+12.5
=23.6-0.74
=22.86