3. Calculaţi:
a) 15-5-2+8:4;
b) [63: (1+2.2+4:2)-4-2]-7-5;
31
c) 9-6-2 [(11 +7.3): 2³+3²];
d) {15 4+15 16-20 [(5²-3² +2³):8-2]}:10.
.