Natural numbers

Problem:

the set of natural numbers between -3 and 9

Solution:

There has been a confusion about what is natural number:

See this for reference:
http://mathworld.wolfram.com/NaturalNumber.html

To be precise, it is better to say positive integer [which include numbers 1, 2, 3, 4, ...] or non-negative integer [which include numbers 0, 1, 2, 3, 4, ...]

Assuming we are talking about positive numbers, the answer is

1, 2, 3, 4, 5, 6, 7, 8, 9

Assuming we are talking about non-negative numbers, the answer is

0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Regrettably, without a precise definition of the natural number your problem is referring to, I cannot be 100% sure which one is the answer you'll need.