int summation =0;

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

void loop() {
  // put your main code here, to run repeatedly:
  summation= Local_addition(9,4);
  Serial.println(summation);
  delay(1000);

  gloabl_addition(9,6);
  Serial.println(summation);
  }

int Local_addition(int a, int b){
  int sum=a+b;
  return sum;
}

void gloabl_addition(int a, int b){
  summation=a+b;
}