Integer vs Long

void setup() {
  // put your setup code here, to run once:
  delay(1000);
  Serial.begin(9600);
  long asAInt = 30 * 10000;
  long asALong = 30 * 10000UL;
  Serial.print("Integer Math: ");
  Serial.println(asAInt);
  Serial.print("Long Math: ");
  Serial.println(asALong);
}

void loop() {
  // put your main code here, to run repeatedly:

}