Mathematics
We know that Natural Numbers are closed under addition (the sum of any two natural numbers is always a natural number). Are they closed under subtraction? Provide a couple of examples to justify your answer.
Answer
Natural numbers are not closed under subtraction because the result of subtracting two natural numbers may not be a natural number.
Example 1 : Consider 3 and 5, both are natural numbers.
⇒ 3 - 5 = -2, which is not a natural number (it is a negative integer).
Example 2 : Consider 7 and 7, both are natural numbers.
⇒ 7 - 7 = 0, which is not a natural number (zero is a whole number, not a natural number).
Hence, natural numbers are not closed under subtraction.
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