If you were to write down the numbers from 1 to 1000000 in order,
For example if you wrote down the numbers from 1 to 20 in order, you'd have
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20.
You would have used 31 digits, 2 zeroes, and the twentieth digit would be
1 (appearing in the 15).