1) (7895 + 5149) – 4895 = (7895 – 4895) + 5149 = 3000 + 5149 = 8149;
2) (227 + 959) – 759 = (959 – 759) + 227 = 200 + 227 = 427;
3) 5797 – (4797 + 270) = (5797 – 4797) – 270 = 1000 – 270 = 730;
4) 1541 – (150 + 541) = 1541 – 541 – 150 = 1000 – 150 = 850.