Fact: If A is a multiple of B then A + B is a multiple of B.
Example: 18 is a multiple of 3, so 18 + 3 = 21 is a multiple of 3.
Using this truth, we can say that the next multiple of 2 after X-3 is X-3+2 or X-1.
The answer is X-1.
Note: It would be no use memorizing the fact at the top of the page. It would
, however, be a good idea to think about it until it makes sense.
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