1. **State the problem:** We are given a conditional statement: "If a number is even, then it is divisible by 2." We are also told the number is not divisible by 2, and we want to conclude whether the number is even or not. 2. **Understand the logic:** The statement "If a number is even, then it is divisible by 2" can be written as: $$\text{Even} \implies \text{Divisible by 2}$$ 3. **Apply the contrapositive rule:** The contrapositive of a conditional statement is logically equivalent to the original statement. The contrapositive of the above is: $$\text{Not divisible by 2} \implies \text{Not even}$$ 4. **Given:** The number is not divisible by 2. 5. **Conclusion:** By the contrapositive, the number is not even. This is a valid logical deduction using the contrapositive rule in propositional logic.