text: function calculateHiddenDigits(firstNumber, secondNumber){
    for(let i=1;i<=9;i++){
      let current = i*100 + firstNumber;
      for(let j=1;j<=9;j++){
        let second_number = j*10 + secondNumber;
        let product = first_number * second_number;
        product = product.toString();
        if(product.length== 5 && product[0]=="5" && product[4]==4){
          console.log(first_number, second_number, product);
        }
      }
    }
  }
  
  calculateHiddenDigits(62, 7);