Integer (Z)= ...-3,-2,-1,0,1,2 3,4...
A.If you add two integers you will get ineger
Like 4 + 5 = 9
Integer+integer=integer
So , you can say integers are closed under addition....
I will give you the top 7 methods to avoid sleep while you are studying:
1) Be Interested in what you are Studying!
Yes to prevent sleep you must make sure that you are Interested in what you are reading!
So...