I also don’t fully understand your question, but from what I do understand, I think you are asking:
Why is it when we type
console.log(7); it prints 7, but then when we type
console.log(3 + 4); the answer of 7 is printed instead of 3 + 4 like in the case of just 7.
From what I am understanding of the lessons so far, arithmetic operators, like + automatically perform tasks in the code when the computer reads it. So the computer sees that there is a + and it is built into the language that when it comes across a + it needs to add the numbers on either side of it. When you wrap the content inside of the parentheses ( ) with quotations ’ ', then the computer sees that as a string, and so it knows to print out exactly what is typed in the string, and not to do the calculation.
I hope this helps, I have just started with JS, so the above is my understanding at the moment.