#define LED_BLINK     12
int a;
int b;

void setup() {
  Serial.begin(9600);
  pinMode(LED_BLINK, OUTPUT);
}

void loop() {
  // Call the function
  lightLED(500,5);
  delay(1000);

  int finalValue = calcValue(50,10);
    Serial.print("a x b = ");
    Serial.println(finalValue);
}

int calcValue(int a, int b){
 int result = a * b;
 return result;
}

void lightLED(int delayTime, int rpt){
  for (int x=0; x<rpt; x++){
    digitalWrite(LED_BLINK, HIGH);
    delay(delayTime);
    digitalWrite(LED_BLINK, LOW);
    delay(delayTime);
  }

}