Răspuns:
Explicație pas cu pas:
35/120+21/27-25/90=7/24+3/9-5/18=21/72+24/72-20/72=45/72-20/72=25/72
5/13+8/13+7/9-4/9-5/6=5/13+8/13+7/9-4/9-5/6=270/702+432/702+546/702-312/702-585/702=702/702+546/702-312/702-585/702=702/702+546/702-312/702-585/702=1248/702-312/702-585/702=936/702-585/702=351/702=1/2
6/5+1 1/8+3/20-2 1/4=6/5+9/8+3/20-9/4=48/40+45/40+6/40-90/40= 93/40+6/40-90/40=99/40-90/40=9/40
5/71+132/142+1 2/4-2=5/71+132/142+6/4-2/1=40/568+528+852/568-1136/568=
=1420/568-1136/568=284/568=1/2