原式=(1-1/2-1/3-1/4-1/5)*(1/2+1/3+1/4+1/5)+1/6*(1-1/2-1/3-1/4-1/5)
-(1-1/2-1/3-1/4-1/5)*(1/2+1/3+1/4+1/5)+1/6*(1/2+1/3+1/4+1/5)
=1/6*(1-1/2-1/3-1/4-1/5+1/2+1/3+1/4+1/5)
=1/6*1
=1/6
原式=(1-1/2-1/3-1/4-1/5)*(1/2+1/3+1/4+1/5)+1/6*(1-1/2-1/3-1/4-1/5)
-(1-1/2-1/3-1/4-1/5)*(1/2+1/3+1/4+1/5)+1/6*(1/2+1/3+1/4+1/5)
=1/6*(1-1/2-1/3-1/4-1/5+1/2+1/3+1/4+1/5)
=1/6*1
=1/6