# How do I use summation notation to write the series 2 + 4 + 6 +... for 10 terms?

##### 1 Answer
Jan 23, 2015

Since these are even numbers you can represent them by $2 n$

And the summation notation then becomes:

${\sum}_{\text{n=1}}^{10} 2 n$ for summing 2+4+....+20

If you wanted to do the same for the first 10 odd numbers,
represented by $2 n - 1$:

${\sum}_{\text{n=1}}^{10} 2 n - 1$