#1**+1 **

∑[n!], n=7 to 2006 ≈2.14586420**1**903033729347689996019583230087×10^5755

**Counting from the left, the 10th digit is 1.** But your question is: "What is the tens digit", which means the second last digit, which is** **a** 4.** Not sure which one you mean!.

Guest Jun 12, 2018

edited by
Guest
Jun 12, 2018

#2**0 **

All you need to add for your purpose are 4 numbers from the start and 4 numbers from the end:

7! + 8! + 9! + 10! +.................+ 2003! + 2004! + 2005! + 2006!=

**2145864201**90..................**40. All the other numbers in between are not going to change the 10th digit from the left, or "tens" digit from the right.**

Guest Jun 13, 2018