Challenge 2 — Solution

Task: Declare let score = 0. Reassign it three times (e.g. += 10
each time), logging score after each reassignment. Then declare
const maxScore = 100 and try reassigning it, observing the error in
the console.

let score = 0;

score += 10;
console.log(score);

score += 10;
console.log(score);

score += 10;
console.log(score);

const maxScore = 100;
maxScore = 200;   // TypeError: Assignment to constant variable.


Expected output (console):

10
20
30
Uncaught TypeError: Assignment to constant variable.


Notes:
- score is declared with let specifically because it needs to be
  reassigned three separate times — const would fail on the very
  first += attempt.
- score += 10 is shorthand for score = score + 10, adding 10 to the
  current value and storing the result back into score.
- maxScore = 200 throws immediately and stops the rest of the script
  from running (in a real file) — const variables cannot be
  reassigned under any circumstances, even to the same value they
  already hold.