sigma notation

[yummymummy1713]

How do you write a sum in sigma notation?

For example: The square root of (3) + the square root of (4) + the square root of (5) + the square root of (6) + the square root of (7) ??

I know that I will be using the E symbol (sigma) but what goes on top, bottom, and to the right?

And how would I find a value of the sum?

If you can explain it to me then I can work it out, but I don't know how to or what to do here.

Thanks.

 

[pka]

The square root of (3) + the square root of (4) + the square root of (5) + the square root of (6) + the square root of (7) ??

\(\displaystyle \L \sum\limits_{k = 3}^7 {\sqrt k }\)