# Problem #5

**Discrete Mathematics**Level 4

How many '1's appear in the following number:

\[12345678910111213141516...9999989999991000000?\]

It is formed by joining the integers from 1 to 1000000 back-to-back and in order. You should be able to see the ? question mark at the back of the number.

This problem is part of the set Easy Problems