fundamentals of math

Question

What is the 21st digit in the decimal expansion of 1/7​?

What is the 5280th digit in the decimal expansion of 5/17​?

Answer 1

1/7 = 0.142857... those 6 digits repeat endlessly

the 6th digit is 7, so is the 12 and 18 and 24 digit or any integer multiple of 6

the 18th digit is 7, the 19th is 1, the 20th is 4, and 21st is 2

5/17 has a decimal with 16 digits that repeat. 5280/16 = exactly 330 with no remainder. the 5280th digit is the same as the 16th digit

5/17 = 0.2941176470588235... the 5280th digit is 5