Show that subtraction and division are not binary operations on `N`.

Explanation

Let a, b `in` N
For subtraction ,
`a,b in N implies a-b notin N, ` for a=3 and b=5
`:.` Subtraction is not a binary operations on N.
For division ,
`a,b in N implies(a)/(b) notin N`, for a=2 and b=3
`:.` Division is not a binary operation on N.
Hence Proved.