text: /**
   * A programming language is said to have
   * First-class functions when functions in
   * taht language are treated like any other
   * variable.
   */
  const add = function(a, b) {
      return a + b;
  }
  
  const subtract = function(a, b) {
      return a - b;
  }
  
  const multiply = (a, b) => a * b;
  
  const divide = (x, y) => x / y;
  
  console.log(add(4, 2));
  console.log(subtract(4, 2));
  console.log(multiply(4, 2));
  console.log(divide(4, 2));
  