4/+-2=+-2
8/+-3= 8/3 sau -8/3
16/rad(16) = 16/+-4= 4 sau -4
99x100/2 : rad(49(1+49) +50)= 99x50 : rad(50(1+49))= 99x50 : rad(50^2) = 99x50 : +-50 = 99 sau -99
