Lab4-Sum of prime number

void setup(){
  size(500,400);
  background(#FFCC33);
  int x = 250;
  int y = 250;
  int firstNum = 0;
  int lastNum = 10;
  textSize(30);
  text("Sum of Prime Number from "+firstNum,x-200,y-100);
  text("to  "+lastNum,x-25,y-60);
  text("is",x,y-20);
  text(+sumOfPrime(firstNum,lastNum),x-10,y+20);
}

int sumOfPrime(int firstNum, int lastNum){
  int x = 2;
  int sum = 0;
  while(x<=lastNum){
    if(primeNum(x)){
      sum+=x;
    }
    x++;  
  }
  return sum;
}

boolean primeNum(int p){
  boolean result = true;
  int x = 2;
  while(x<p){
    if(p%x == 0 || p==1 ){
      result = false;  
    }
    x++;
  }
  return result;
}