Question 859710
Natural numbers are "counting numbers".  They are positive whole numbers that you would use to count objects.
.
Which of those fall under that definition?  If you were counting apples, what could you use to count them?
.
7 is obvious.
The negatives are obviously not.
What about 0?  Can you "count" zero?  The true answer is "no", although I have seen texts that dispute that.  It's not a natural number.  You don't start counting with zero, you start with "one".
{{{1/3}}} is not a whole number, so no.  No for 7.8 for the same reason.
What about the square root of 25?  Tricky :-).  It's 5, so it IS a natural number.  Whether you write it as sq rt 25 or 5, it's the same number.