Question 338521
The natural numbers are the positive integers 1,2,3...
The opposite of a natural number would be the negative integers -1,-2,-3,...
Negative integers are not part of the natural numbers. 
So you can use 1 and -1 as a counterexample.
.
.
.
1 is an integer.
The reciprocal of 1 is 1/1=1 is also an integer.