1)(176+343)-243 = (343-243)+176=100+176=276
2)(684+915)-484 = (684-484)+915=200+915=1115
3)(259+101)-59 = (259-59)+101 = 200+101=301
4)1287-(487+164) = (1287-487)-164=800-164=636
5)971-(235+371) = (971-371)-235=600-235=365
6)5393-(1393+158) = (5393-1393)-158=4000-158=3842