3 运动定律与简便运算
用简便方法计算.
(1)47×0.125×8
(2)0.65×201
(3)0.02×48.8×50
(4)1.45×6.5+0.55×6.5
(5)0.625×0.8×0.04×0.5
(6)18.8×101﹣18.8.
数学门诊.(把不对的改正过来)
(1)1.7×0.31+0.69×1.7
=1.7×(0.31+0.69)×1.7
=1.7×1×1.7
=2.89
改正:
(2)0.25×12
=0.25×(4×3)
=0.25×4+0.25×3
=1+0.75
=1.75
改正:
(3)3.5×103
=3.5×100+3
=350+3
=353
改正:
利用你发现的规律,计算下面各题.
88×33+12×33
125×4×25×8
2009+2009×99
58+39+42+61
264+56+36
125×88.