Răspuns:

9. 1375+758=2133

4207-2853=1354

685×27=18495

10. a) 1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=1275

b) 11×{8×[7×(32×8-250)-36]-46}=11×{8×[7×(6-36)]-46}=11×[8×(42-36)-46]=11×(8×6-46)=11×(48-46)=11×2=22

11. a) 175×235+13×175-175×48=175×(235+13-48)=175×200=35000

b) 7+14+21+...+280=7×(1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40)=5740