This site is mobile accessible. Press the "Tap Here" button to use a smaller font-size.
Smartphone icons created by Freepik - Flaticon
The result of adding "5" + 2 + 3 is:
let x = "5" + 2 + 3;
document.getElementById("demo").innerHTML = x;
If you put a number in quotes, the rest of the numbers will be treated as strings, and concatenated.