How to utilize date add function in Google spreadsheet?

Question

I believe the issue I am having now should be much easier in MS Excel. However, since my company uses Google Spreadsheet so I have to figure out a way.

Basically, I have

Answer 1

=TO_DATE(TO_PURE_NUMBER(Insert Date cell, i.e. AM4)+[how many days to add in numbers, e.g. 3 days])

Looks like in practice:

=TO_DATE(TO_PURE_NUMBER(AM4)+3)

Essentially you are converting the date into a pure number and back into a date again.