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简介:
一、乘法分配律
(1.25-0.125)×8 (125+2.5)×0.8
=1.25×8-0.125×8 =125×0.8+2.5×0.8
=10-1 =1+1
=9 =2
二、把其中一个因数分成两个数的和或差,再按乘法分配律
3.65×10.1 0.32×403
=3.65×(10+0.1) =0.32×(400+3)
=3.65×10+3.65×0.1 =0.32×400+0.32×3
=36.5+0.365 =128+0.96
=36.865 =128.96
三、更改因数的小数点位置
46×57+23×86 4.8×7.8+78×0.52
=46×57+46×43 =4.8×7.8+7.8×5.2
=46×(57+43) =7.8×(4.8+5.2)
=46×100 =7.8×10
=4600 =78