[0,(8)-5supra6].0,9.11

Răspuns :

0,(8)=8/9
0,9=9/10
=(8/9-5/6)x9/10x11
=[(8x2-5x3)/18]x99/10
=1/18x99/10=simplif cu9
=1/2x11/10=11/20=0,55