How does one change the top number in a summation?

Question

Sorry I do not know the correct term (I am guessing "upper limit"). Here is what I mean. $$\sum\limits_{i=1}^{\color{red}{17}}\frac{2i}{i+3}$$ The $17$ is what I am talking about as "the top number". Is there a way to change it to something like $5$? $$\sum\limits_{i=1}^{\color{red}{17}}\frac{2i}{i+3}=\sum\limits_{i=1}^{\color{green}{5}} \ \ \ \ \ \text{<--- What goes over there?}$$ I could not find any solution online, so I suspect that it is impossible to do so.