# I am perplexed

**Discrete Mathematics**Level 5

Let \(N\) be a \(2n\) digit number with digits \(d_{1},d_{2},d_{3},...,d_{2n}\) from left to right \(i.e\) \(N= \overline {d_{1}d_{2}....d_{2n}}\) where \(d_{p}\) is not equal to \(0\) , \(p=1,2,...,2n\). Find the number of such \(N\) so that the sum \[\sum_{q=1}^{n}d_{2q-1} \times d_{2q}=even\] for \(n=7\) .