Add ajax form to wordpress

I need a new page added in my wordpress site. Page should have a simple html form with several inputs and when hitting "Calculate" button it should simply send an ajax request (without refreshing the page), calculate a simple PHP function with the provided fields, return a result and present it as a label in the page. Please see mockup with the form, the result should be: first_number*second_number*multiply*negativity first_number can be 1,2,3,4 second_number is free text multiply can be 2 or 5 negativity is 1 (unchecked) or -1 (checked) Please notice that it must be ajax, it means no refresh of the page. Thanks