Question

1－2＋3－4＋5－6＋．．．．．＋1991－1992＋1993＝小学四年级

祥细的步骤

Answer 1

(1+2)+(3-4)+(5-6)+...........+(1991-1992)+1993=-996+1993=997

Answer 2

解：1-2+3-4+5-6+······+1991-1992+1993=[(1+1993)*(1+1993)/4]-[(2+1992)*(2+1992)/4]=997

Answer 3

1993-1992/2=997

Answer 4

找规律
1-2=-1
-1+3-4=-2
-2+5-6=-3
-3+7-8=-4
...........
最后结果
-996+1993=997

Answer 5

=(-1)+(-1)+(-1)+......+(-1)+1993
=(-1)*(1992/2)+1993
=(-1)*996+1993
=-996+1993
=997