Question

用简便算法计算。

2.5×32×12.5 4.83-1.56+0.16-2.44 2/5×7+2/5×2+2/5
2.5×32×12.5
4.83-1.56+0.16-2.44
2/5×7+2/5×2+2/5

Answer 1

一:2.5×32×12.5
=2.5*4*8*12.5
=(2.5*4)*(8*12.5)
=10*100
=1000
二:4.83-1.56+0.16-2.44
=4.83-(1.56-0.16+2.44)
=4.83-3.84
=0.99
三:2/5*7+2/5*2+2/5
=2/5*7+2/5*2+2/5*1
=2/5*(7+2+1)
=2/5*10
=4

Answer 2

2.5×32×12.5 =(2.5×4)×(8×12.5)=10×100=1000
4.83-1.56+0.16-2.44 =4.83-(1.56-0.16)-2.44=4.83-(1.4+2.44)=4.83-3.83-0.01=0.99
2/5×7+2/5×2+2/5=2/5×(7+2+1)=2/5×10=4

Answer 3

2.5×32×12.5＝2．5×4×8×12．5＝10×100＝ 1000
4.83-1.56+0.16-2.44 ＝4．83＋0．16－1，56－2．44＝4．99－4＝0．9
2/5×7+2/5×2+2/5＝2／5×（7＋2＋1）＝2／5×10＝4

Answer 4

可以写成2.5*4*8*12.5然后下同