1994+12-113+212-313+412-513+…[phone]．

Question

1994+(1)/(2)-1(1)/(3)+2(1)/(2)-3(1)/(3)+4(1)/(2)-5(1)/(3)+…+1992(1)/(2)-1993(1)/(3)．

Answer 1

原式=1994-[（1(1)/(3)−(1)/(2)）+（3(1)/(3)− 2(1)/(2)）+…+（1993(1)/(3)−1992(1)/(2)）]，
=1994-(5)/(6)×（1994×(1)/(2)），
=1994-(5)/(12)×1994，
=1994×(7)/(12)，
=1163(1)/(6)．