Question

简便计算：0.72X87.5+8.75X0.28

写埋过程啊！！

Answer 1

=0.72*25*3.5+0.28*25*0.35
=4*0.18*25*3.5+0.07*4*25*0.35
=100*0.18*3.5+100*0.07*0.35
=100*0.09*2*3.5+100*0.07*0.07*5
=100*0.09*7+100*7*0.0007*5
=100*7(0.09+0.0035)
=100*7*0.0935=7*9.35=65.45

Answer 2

0.72X87.5+8.75X0.28
＝0.72*0.1*8.75+8.75*0.28
＝（0.072+0.28）*8.75
＝0.352*8.75

Answer 3

=（0.72*10）*（87.5/10）+8.75*0.28
=7.2*8.75+8.75*0.28
=8.75*（7.2+0.28）
=8.75*7.48
=65.45

Answer 4

0.72*87.5+8.75*0.28=72/100*700/8+7/8*28/100（最重要的是要知道7/8=0.875这一点，利用约分，两步就可求出）=63+2.45=65.45