86*21-86*59+86*59-59*21=21(86-59)=21*27=467
86 . ( 21 - 59 ) + 59 . ( 86 - 21 )
= ( 86 - 86 ) . ( 59 - 59 ) . ( 21 - 21 )
= 0 . 0 . 0
= 0
=86*21-86*59+86*59-59*21
=86*21-59*21
=(86-59)*21
=31*21
=651
86 . ( 21 - 59 ) + 59 . ( 86 - 21 )
= ( 86 - 86 ) . ( 59 - 59 ) . ( 21 - 21 )
= 0 . 0 . 0
= 0