I need calculation cards that allow you to calculate percentage, divide, multiply, etc.

I need cards that calculate based on data from other cards.

For example: I have a card that shows 191 tasks, I want to divide that number by another card that contains a number of 20 tasks.

Another example: I need cards that add up tracked time from linked tasks. I need to measure how many hours were spent on certain Customers.

In short: I need the Dashboards to present me indexes, percentages, rates, etc. Based on data from custom fields, tracked time, time estimate, number of tasks, etc.