Question

53×57-47×43 简便算法...

麻烦具体点...

Answer 1

(47+10)*(43+10)-47×43
=47*43+47*10+10*43+10*10-47*43
=47*10+10*43+10*10
=(47+43)*10+100
=900+100
=1000

Answer 2

53×57-47×43
=53×57-(57-10)×43
=53×57-57×43+10×43
=57×(53-43)+10×43
=(57-43)×10
=140