Please help-I need to write 4+6+8+10 in sigma notation

would it be sigma sign in middle (3) on top of sign, n=0 on bottom of signma notation and to the right it would be (4+2n)
so it would look like--

(3)
(sigma in middle) (4+2n)
n=0

Yours will work

If I recall, the index in sigma notation usually starts with 1, so you could have

4
∑ (2+2n)
n=1

There is no unique way to state the result.