I dona understand why the beginning of the question is not considered in the answer. It is said there that the original number is even. So, I added 2 to all the possibilities and shifted the digits. The only one that, when adding a 2 would be greater than its original version (12) shifted (21) was 1. Don't understand how in the example we are using numbers 73 or 69, since they are not even numbers, as indicated at the beginning of the question.
Thanks

Ilse, even numbers end with 0, 4, 6, 8, too, not just 2. So there is a flaw in your method.

I agree with you that the wording of Method 1 in the explanation is really confusing. All it is saying is, if you list all the even numbers between 90 and 98, e.g., 90, 92, 94, 96, 98, and inspect the "reverse": 09, 29, 49, 69, 89, none will be larger.

Whereas in the other cases, there is always an even number greater than itself, e.g., 2, 4, 6, 8 are larger than 1, 3, 5, or 7. For example, 12 is less than 21. 34 is less than 43. 56 or 58 are less than 65 or 85, and 78 is less than 87.

Regards, my question is about the question itself, two digit even, when reversing it its digits, the odd will be greater,
Means for example 20, reversing is 02, right?!
So in this case isn't the right answer is 1
So 12, 14, 16, 18 will all work, 21, 41, 61, 81
98 will be 89 so it doesn't work, that's how I understand the question, thanks

Sudad, any of the answer choices except 9 will satisfy the rule. The question is asking which will NOT satisfy the rule.