Ex 8!! Va rog frumos! dau coroana

Un exemplu:
(a/6)•(b/7)=1/2
(a•b)/42=21/42
a•b=21
7/6 •3/7=1/2; 7/6 si 3/7 sunt fractii periodice
=>1/2= 1,1(6)• 0,(428571)
verificare:
(116-11)/90•428571/999999=105/90 •3/7=
=7/6 •3/7=3/6=1/2 (A)