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