Arduino get keyboard input

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial.setTimeout(10);
}

void loop() {
  // put your main code here, to run repeatedly:
  Serial.println("Enter 1st number");
    int num = getNextNumber();
  Serial.println(num);

  Serial.println("Enter 2nd number");

  int num1 = getNextNumber();
  Serial.println(num1);

  Serial.println("Select an option for calculation:");
  Serial.println("1 - addition");
  Serial.println("2 - subtraction");
  Serial.println("3 - multiplication");
  Serial.println("4 - division");
  Serial.println("Enter your selection");

  int select = getNextNumber();
  if (select >= 1 && select <= 4) {

    if (select == 1) {
      Serial.print(num);
      Serial.print("+");
      Serial.print(num1);
      Serial.print("=");
      Serial.println(num + num1);
    }

    if (select == 2) {
      Serial.print(num);
      Serial.print("-");
      Serial.print(num1);
      Serial.print("=");
      Serial.println(num - num1);
    }
    if (select == 3) {
      Serial.print(num);
      Serial.print("*");
      Serial.print(num1);
      Serial.print("=");
      Serial.println(num * num1);
    }
    if (select == 4) {
      Serial.print(num);
      Serial.print("/");
      Serial.print(num1);
      Serial.print("=");
      Serial.println(num / num1);
    }
  }
  else {
    Serial.println("Wrong selection, try again");
  }

}

int getNextNumber(){
  while (Serial.available() == 0);
  return( Serial.parseInt());
}