Correct. But this applies to religion and specific claims. In the analogy you give, religion may give answers the properties of which may be validated through some known parameters. This is not atheism. This is seeking. The theist only goes as far as saying an answer exists which must, for example necessarily have the two numbers as factors, must be an even number, must be greater than either number and so on.

The atheist position, to me, is more one of there is no answer and not I don't know. I don't know does not try to assert such absurdities as "causality may not apply to some forms of matter" even though there is nothing suggesting the possibilities probability of such an idea.