如题所述
第1个回答 2021-08-05
72x79=72(80-1)=72x80-72=5760-72=5688
第2个回答 2021-08-04
解:原式=72*80-72*1=5760-72=5688
第3个回答 2021-08-05
=72*(80-1)
=72*80-72
=8*9*80-8*9
=9*(8*80-8)
=(10-1)*(640-8)
=(10-1)*632
=6320-632
=6320-320-312
=6000-312
=5688
=72*80-72
=8*9*80-8*9
=9*(8*80-8)
=(10-1)*(640-8)
=(10-1)*632
=6320-632
=6320-320-312
=6000-312
=5688
第4个回答 2021-08-05
72*79
=72*(80-1)
=72*80-72
=5760-72
=5688
=72*(80-1)
=72*80-72
=5760-72
=5688
第5个回答 2021-08-04
72x79
二72x(80一1)
二72x80一72
二5760一72
二5688
二72x(80一1)
二72x80一72
二5760一72
二5688