7. Efectuați: a) (303 + 404 +505): 606; b) 40+ 8. (4+3.4); 40+ 40:40 - 40; 475.5-475 : 5; 2+2[2 + 2 · (2 +2 : 2)]; 2.802 + 109.8 -- 204 510 : 102; 200 - 9.16 + 12.12 - 25. 7; 14. [24 - 325: (18.4-7)]; 5.12 - 2. (30 - 27:3); 1 004 - 4.(8:22 + 402 : 2). c){20 - 10.[211-7. (24+24:4)]}: 10 - 1; [72.8-16. (3 +124: 62) - 143: (76-5. 13)]: 3; 15+ {250:5+315:3. [160 - (50 : 25+2).40]}. .​