Like this

for (int i = 1; i <= n; ++i)
    sum += i * i;

To insert a code fragment you must put line, consisting of five twiddles: ~~~~~, before and after the code.

`~~~~~

for (int i = 1; i <= n; ++i) sum += i * i;

~~~~~ `

To use latex formulas, you must enclose in with dollar sign $\sum\limits_{i=1}^{n}{i^{2}}$

`~~~~~

for (int i = 1; i <= n; ++i) sum += i * i;

~~~~~ `

$$$\prod\limits_{i=1}^{n}{i^{2}}={(n!)}^{2}$$$

$$$\sum\limits_{i=1}^{n}{i^{2}}={2*{n^{2}}}$$$

$$$a_{n}-a_{n-1}$$$

i tryied above can be done by inclosing following inside "$" sign

• \prod\limits_{i=1}^{n}{i^{2}}={(n!)}^{2}

• \sum\limits_{i=1}^{n}{i^{2}}={2*{n^{2}}}

• a_{n}-a_{n-1}