Save the result of a method in a class

I want to save or store the outcome of a property in a class to use in another property in the same class. How do I do that?

for example:

class MyClass {

  get randomNumber() {
    let number = Math.floor(Math.random() * 10) + 1
    return number
  }

  get newSum() {
    return this.randomNumber + 1 // I want to use the result from the previous property and add 1 to that
  }

}

```