2(10×10+1/2)-(1+2+3+...+20)-(2+4+6+...+20)=
2×55-210-2×55=
110-210-110=
-210
sper ca te-am ajutat :)
Răspuns:
2+4+6+........+20
1×2+2×2+2×3+.........+2×10
2(1+2+3+.........+10)
2×10×4÷2
2×10×2
2×20
