Which of these are not a natural number ?

Subtract these :

255-35

Randy Rabbit had 347 carrots. He ate 19 carrots. How many carrots does he have left?

What is the sum of 45,009 and 3,008?

The number of person visited the holy shrine of mata Vishnu Devi during last two year was 1,37,89,509 and 1,29,76,498 respectively. How many person visited the shrine during these two years?