=(17-16)-(15-14)+(13-12)-(11-10)+(9-8)-(7-6)=1-1+1-1+1-1=0
17一16一15十14十13一12一11十10十9一8一7十6=(17-16)-(15-14)+(13-12)-(11-10)+(9-8)-(7-6)=1-1+1-1+1-1=0
17-16-15+14+13-12-11+10+9-8-7+6=(17-16-15+14)+(13-12-11+10)+(9-8-7+6)=0+0+0=0