Jekyll page rating calculator with meta from Front Mater area

I am editing include/span with the following code pretend to be as "Jekyll page rating calculator with meta from Front Mater area" but it seems like some syntax missing an extra heading/lines to let calculation to display in left bottom round quotes. Now there is no value

See the sampl page

<span class="indexmod">{% assign number_of_words = content | strip_html | number_of_words %}{% assign social = page.facebook | plus: page.instagram %}{% comment %}Two lines for readability, but can be chained on one line{% endcomment %}{% assign Indexmod = social | times: page.age | divided_by: 1000000.0 %}{% assign Indexmod = Indexmod | times: number_of_words | divided_by: 100  %}{% endunless %}</span>