number string

The counting numbers are written out as one long string: 123456789101112 … What is the 100th digit in the string? Show how you solved it! Show your work.
 
William Graham, B. Sc., Computer Science, University of Calgary, answered today on Quora.
 
First, he solved with Python script, and then he said, “It’s easily verified by splitting the string into lines of 10 digits each, and looking at the tenth digit of the tenth line.”
 

• 1234567891 
• 0111213141 
• 5161718192 
• 0212223242 
• 5262728293 
• 0313233343 
• 5363738394 
• 0414243444 
• 5464748495 
• 0515253545 
• 5 

The answer is 5.