Question

(-二分之一)+(+三分之一)+(-四分之一)+(+九分之一)+(+八分之一)+(-九分之四)=

Answer 1

原式=(-1/2)+(+1/3)+(-1/4)+(+1/9)+(+1/8)+(-4/9)

=[(+1/9)+(-4/9)]+(+1/3)+[(-1/2)+(-1/4)]+(+1/8)

=[-(4/9-1/9)]+(+1/3)+[-(1/2+1/4)]+(+1/8)

=[(-1/3)+(+1/3)]+[(-3/4)+(+1/8)]

=0+[-(3/4-1/8)]

=-(6/8-1/8)

=-5/8