What is the 125th digit beyond the decimal point in the decimal representation of 4/7?
The 125th digit is 1.
4/7 = 0.571428571428571428.....etc
Groups of 6 digits repeat. 125 = 5 mod(6), and the 5'th digit of the 6 repeating digits is 2, so this is the 125'th digit beyond the decimal point.