text: function multiplyAll(arr) {
      var product = 1;
  
      for (var i = 0; i < arr.length; i++) {
          for (var j = 0; j < arr[i].length; j++) {
              product *= arr[i][j];
          }
      }
  
      return product;
  }
  
  var product = multiplyAll([[1,2],[3,4],[5,6,7]]);
  
  console.log(product);