Use a calculation for a search component to display a list

Hi all,

I watched the video from @tim.young today with the custom views with the search function. Especially playing around with the dates struck me, since I am struggling with something at this time.

I have a search table where people can look up rates for their mortgage. The rate is dependent upon how much they want to loan (the LTV)… LTV is determined by a formula : " requested mortgage/ home value.

The aim is to use the home value and mortgage as input fields, and then run something so that Tadabase knows to look for the rates corresponding to the particular TLV…
I have an example:
The hhome value is 300.000 (input)–> the mortgage is 160.000 (input). The LTV is 0.5333 (calculated).
The LTV is crucial for the data table, since the datable has LTV columns (min and max).

Question: how can I structure this… the current option is to let the user calculate the LTV itself, but it would be more user friendly to let TB do this.
I have attached some screenshots for clarification: