text: function calculator(a, b, symbol) {
  
      switch (symbol) {
          case "+": {
              console.log(add(a, b));
          }
              break;
          case "-": {
              console.log(substract(a, b));
          }
              break;
          case "*": {
              console.log(multiply(a, b));
          }
              break;
          case "/": {
              console.log(divide(a, b));
          }
              break;
      }
      function add(a, b) {return a + b};
      function substract(a, b) {return a - b};
      function multiply(a, b) {return a * b};
      function divide(a, b) {return a / b};
  }
  
  
  calculator(2, 4, '+');
  calculator(3, 3, '/');
  calculator(18, -1, '*');
  