If you want to add 27 to x, you can do it like this:

let x = 5;
x = x + 27;
console.log("x equals " + x);
// x equals 32

But since we increment values so often, we like to use the += operator as a shorthand. Instead of x = x + 27, we can enter x += 27 and get the same result. In other words, x += 27 is equivalent to x = x + 27.

Knowing that, can you simplify the line a = a + 12; using the += operator?