简便运算 1989×1999-1988×2000
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简便运算 1989×1999-1988×2000
简便运算 1989×1999-1988×2000
简便运算 1989×1999-1988×2000
1989*1999-1988*2000
=1989*1999-1988*(1999+1)
=1989*1999-1988*1999-1988
=1999(1989-1988)-1988
=1999-1988
=11
=1989*(1898+10)-(1989-1)*(1989+20)
1989*1999-1988*2000
=1988*1999+1999-1988*2000
=1988*(1999-2000)+1999
=-1988+1999
=11
1989×1999-1988×2000
=1989×1999-1988×(1999+1)
=1989×1999-1988×1999-1988
=(1989-1988)×1999-1988
=1999-1988
=11
=1989(2000-1)-1988X200
=1989X2000-1989-1988X2000
=(1989-1988)X2000-1989
=2000-1989
=11
1989×1999-1988×2000
=1989×(2000-1)-1988×2000
=1989×2000-1988×2000-1989
=(1989-1988)×2000-1988
=2000-1988
=12
1989×1999-1988×2000
=1989×(2000-1)-1988×2000
=1989×2000-1989-1988×2000
=(1989-1988)×2000-1989
1*2000-1989
=2000-1989
=11
1989×1999-1988×2000
=(1988+1)(2000-1)-1988×2000
=1988×2000+2000-1988-1-1988×2000
=2000-1989
=11
1989×1999-1988×2000 =
(1988+1)×1999-1988×2000 =
1988×1999+1999-1988×2000 =
1988×(1999-2000)+1999=
-1988+1999=11