SharePoint list conditional formulas

I've read the article https://docs.microsoft.com/en-us/sharepoint/dev/declarative-customization/list-form-conditional-show-hide plenty of times so I know how to make a column visible if a specific choice is selected e.g. "Show if column Title equals A" would be written as...

=[$Title]=='A'

Is it possible to write one such formula to say "Show if column Title starts with A" instead? Also, is there a more detailed guide to writing these formulas out there?