Important 2020 summer's update
You can use such functions: Minimum/Maximum, Ceil up/down.
You can perform more complex logical and arithmetical calcualtions by using the Scripts.
Please, click here to learn more about how to use the scripts and functions.
You can select the record template for the "Link to Record view" option.
Just create the Formula field, activate the "Link to Record view" option in the 'Advanced' section:
As you can see you'll be able to choose any record template from the current table. This way you can even create the several formula fields, by click on each the different record template will be applied to the record view.
In the 'Settings' tab for the relationship field you can activate the new option "Show 'Add' link in subform".
Once enabled, you'll be able to add new entries to the link form when it's opened as a subform.
In the subform field you can also activate the new option - "Show record number". And it will obviously show you the subform entries number in a table view.