Răspuns:
Explicație pas cu pas:
a) (13-1)/90-11/6=12/90-11/6=12/90-165/90=-153/90
b)4/10+9/5-51/2=(4+9x2-51x5)/10=(4+18-255)/10==-233/10
c)45/11-15/22+5/2=(45x2-15+5x11)/22=(90+55-15)/22=130/22
d)23/99-10/33-5/2=(23-30)/99-5/2=-7/99-5/2=-(7x2+5x99)/198=-509/198