I have a spreadsheet that performs once-off calculations on inputted data. 

I made the input fields editable and locked the other fields, and that works on a desktop browser (Firefox).

However those fields are not editable on a mobile browser (Firefox or Chrome for iOS).

I created a form to test which does input data very nicely on the same mobile browsers; but does not appear to be able to connect to a calculation spreadsheet. Is this possible? Or is there another way to achieve this outcome?