If you write 1 to 1000000 how many single digits are there?

There are 9 single digits (1, 2, 3, 4, 5, 6, 7, 8, 9) that are repeated throughout the numbers from 1 to 1000000. Each single digit appears 100,000 times (except for 0, which appears 100,000 times as well). Therefore, there are a total of 900,000 single digits in the range from 1 to 1000000.