Yes, 19 is a natural number
It is both.
√225 = 15 so it is a natural number.
Yes, every natural number is a whole number.
Yes, it is a natural number.
yes, 3 is a natural number. any positive number is.
YES. 101 is a natural number.
Yes it is considered as a natural number.
Yes it is considered as a natural number.
No. Example: The difference of 2/5 & 1/3: 2/5 - 1/3 = 1/15 ∈ ℚ (is a rational number) ∉ ℕ (is not a natural number).
It is a natural number.
No a natural number is 1,2,3,4 etc