简便运算 9876×6789-9877×6788

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简便运算 9876×6789-9877×6788

简便运算 9876×6789-9877×6788
简便运算 9876×6789-9877×6788

简便运算 9876×6789-9877×6788
=9876*6788+9876-9877*6788
=(9876-9877)*6788+9876
=9876-6788
=3088
好想你们还没有学到负数,这样
=(9877-1)*6789-9877*6788
=9877*6789-6789-9877*6788
=9877*(6789-6788)-6789
=9877-6789
=3088

9876*6789=(9877-1)*(6788+1)=(9877*6788)+9877-6788-(1*1)(就不知道学过这个展开没有)
原等式=9877-6788-1=3088

9876*6789-9877*6788=9876*(6788+1)-(9876+1)*6788
=9876*6788+9876-9876*6788-6788
=9876*6788-9876*6788+9876-6788
=0+9876-6788
=9876-6788
=3088

9876×6789-9877×6788
=9876×6789-9876×6788-6788
=9876*(6789-6788)-6788
=9876-6788
=3088

9876(6788+1)-(9876+1)*6788=9876*6788+9876*1-9876*6788-1*6788=9876-6788=3088

(9677-1)*(6788+1)-9877*6788
=9677*6788+9677-6788-1-9877*6788