你好,这道题的简便算法如下:
72×28-1400
=72×28-50×28
=(72-50)×28
=22×28
=20×28+2×28
=560+56
=616
望采纳。
=(70+2)×28-1400
=70×28+2×28-70×20
=70×(28-20)+56
=70×8+56
=560+(60-4)
=560+60-4
=616
脱式计算:
72×28-1400
=(70+2)×(20+8)-1400
=1400+560+40+16-1400
=(1400-1400)+(560+40)+16
=600+16
=616