The JS snippet I created relies on the forloop.counter variable being available within a {% for key, value in data.items %}..{% endfor %} tag.
{% for key, value in data.items %}..{% endfor %}
Is there
Use django-mathfilters. The addition filter doesn't coerce numbers to integer so you can add floats:
addition
{% load mathfilters %} {{ num1 | addition:num2 }}