Hi, I'm taking AS Maths Core 1 in January. I am stuck on a question in the text book.

It goes like this:

Calculate:

5

Sigma r(r+1)

r = 0

The answer in the text book is 112 but I can't get that. I get 70 as an answer. I would really appreciate any help with how to solve this particular problem.]

Thanks in advance,

j