小数和分数的混合运算,我们要把小数化成分数计算,这样才会快
2=10/5 五分之十
0.6=3/5 五分之三
(10/5-3/5)*15/7=7/5*15/7=15/5=3
(-0.125)×(-7分之4)×8×(-7)
=(-8分之1)×8×(-7分之4)×(-7)
=(-1)×4
=-4
12/7-5/7+30%
=(12-5)/7+0.3
=1+0.3
=1.3
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如对本题有疑问可追问,Good luck!
二点五加〔(七分之四加零点六)减七分之三〕乘十三点五
=5/2+(4/7-3/7+3/5)X27/2
=5/2+27/14+81/10
=35/14+27/14+81/10
=31/7+81/10
=310/70+567/70
=877/70
结果是19,具体过程如下:
30-63×(7分之2-9分之1)
=30-63×7分之2+63×9分之1
=30-18+7
=12+7
=19
(3又3/7+0.8+3/8)×1.25
=24/7×5/4+0.8×5/4+3/8×5/4
=4又2/7+1+15/32
=5又169/224
56%×3/7-0.6×3
=0.24-1.8
=-1.56
(-0.6)×(-2/9)
=0.6×2/9
=6/10×2/9(约分)
=2/5×1/3
=2/15
零点六变成五分之三,然后与九分之二通分!就可以了!望采纳!