python
#urls.py: 
    ...
    path('<int:pk>/some-page/', some_page, name='some_page'),
    path('<int:pk>/do-math/', math_html_fragment, name='do_math'),
    ...

#views.py:
def some_page(request):
  # Typical rendered html page, contains the html with htmx tags
  return render(request, 'some-page.html', ...)

@require_POST
def math_html_fragment(request): 
  # Do stuff with request.POST dict
  dummy_value = 5  
  ...
  return HttpResponse(dummy_value)

#some-page.html
...
<some-tag hx-post="{% url 'do_math' (some pk) %}"> 
...