Counting Cards- Why do I have to use ++ and --?

Tell us what’s happening:
Why can’t I use count+1 and count-1 instead of count++ and count–?

Your code so far

var count = 0;

function cc(card) {
  // Only change code below this line
        case 2:
        case 3:
        case 4:
        case 5:
        case 6:
        case 10:
        case "J":
        case "Q":
        case "K":
        case "A":
      if (count > 0){
        return count + " Bet";
      } else {
        return count + " Hold";

  // Only change code above this line

// Add/remove calls to test your function.
// Note: Only the last will display
cc(2); cc(3); cc(7); cc('K'); cc('A');

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36.

Link to the challenge:

Because count + 1 would need to be assigned back to count for it to change the value of count. The ++ operator is like writing count = count + 1.

You don’t have to use count++. You could use something that is equivalent: count += 1 or count = count + 1.