Multiple choice The sum of the series 1.2.3+2.3.4+...3.4.5.+...to n terms is $n(n+1)(n+2)$ $(n+1)(n+2)(n+3)$ $\frac { 1 }{ 4 } n(n+1)(n+2)(n+3)$ $\frac { 1 }{ 4 } (n+1)(n+2)(n+3)$ Reveal answer Fill a bubble to check yourself A Correct answer