Answer:
1000
Step-by-step explanation:
The successor of 999 is 1000
999+1=1000
SUCCESSOR
The number which comes immediately after a particular number is called its successor. The successor of a whole number is the number obtained by adding 1 to it. Clearly, the successor of 0 is 1; successor of 1 is 2; successor of 2 is 3 and so on.
