How to calculate result from fields inserted?
Such page can be creating using various approaches, as further explained below.
Using Views and Views Calc
Use the Views module, together with the Views_Calc module. Here is a quote about Views_Calc (from its project page):

... adds simple calculations to a views table. Requires the Views module.
You can SUM, AVERAGE, COUNT, MIN, MAX, or AVG selected columns. A plug in theme makes the view look more spreadsheet-like (right justifies numeric fields, shades calculated columns and rows, and underlines calculated rows).
You can also create custom dynamic fields that can be used in any view using SQL snippets like CONCAT('field_first_name', ' ', 'field_last_name') or DATE_FORMAT(node.created, '%m/%%d/%Y'). The custom fields are set up in admin/settings/views_calc.

Refer to the question about How can I show average votes of fivestar nodes? for some screenprints about how to use this module.
Using Forena
If you'd want to &quot;roll your own cookies&quot; (i.e. some report that perfectly fits your custom requirements), then you might want to consider the Forena module. Here is an excerpt about that from its Community documentation:

Forena Reports is built of the idea of using SQL to get data out of a database and use XHTML and CSS to format it into web reports.
It is designed to leverage existing knowledge of HTML, CSS, SQL and JavaScript to help you create rich interactive web reports.

For an example of such custom report, created with Forena, start from the statistics (summary info) of the Watchdog Statistics, as in this Watchdog Statistics sample. Note the red numbers to the right of the table, which are actually hyperlinks that can be used as drill-down reports. I.e. if you click on any of them (like the &quot;2&quot; for &quot;Page not found&quot;), you get a details report about (in this case) the 2 specific records related to the &quot;Page not found&quot;). More details about this specific case can be found in comment #2 of issue 2337327. Obvious, I didn't really do any effort to beef up the look-and-feel of that report, like background, etc.
Disclosure: I'm a co-maintainer of Views_Calc and Forena,
I hope this does not violate the site's policy on self-promotion.