Find the sum:
ThHTO+12536342
First add ones 3+2=5
Next add tens 5+4=9
Next add hundreds 2+3=5
And finally add thousand 1+6=7
So we get,
ThHTO+125363427595
Find the sum to n terms of the series 1 × 2 × 3 + 2 × 3 × 4 + 3 × 4 × 5 + …