Regula adunarii fractiilor: aducerea termenilor la numitor comun. Observam ca cel mai mare numitor este 3^6. Aducem toate fractiile la acest numitor, amplificand cu numarul potrivit
Deci:
1/3 + 1/3² + 1/3³ + 1/3⁴ + 1/3^5 + 1/3^6 = (1*3^5)/(3*3^5) + (1*3⁴)/(3²*3⁴) + (1*3³)/(3³*3³) + (1*3²)/(3⁴*3²) + (1*3)/(3^5*3) + 1/3^6= 3^5/3^6 + 3⁴/3^6 + 3³/3^6 + 3²/3^6 + 1/3^6= (3^5+3⁴+3³+3²+1)/3^6=(243+81+27+9+1)/729= 361/729.
