Math 6

Question Analysis
This question tests understanding of subtraction with natural numbers and the closure property of natural numbers under subtraction.
It requires identifying which subtraction yields a result that remains within the set of natural numbers.

Key Concept Explanation
Natural numbers = {1, 2, 3, ...} (positive integers).
Closure under subtraction:
Natural numbers are not closed under subtraction because subtracting a larger number from a smaller one yields a non-natural result (zero or negative).
Only cases where minuend > subtrahend produce natural numbers (e.g., 8 − 3 = 5).

Step-by-Step Solution
Evaluate each option:
A. 5 − 7 = −2 (negative → not natur...