Question 6
Find the possible values of $m$ such that the 101-digit number below is divisible by 7. $$\underbrace{66\ldots6}_{50\text{ digits}}\,m\,\underbrace{55\ldots5}_{50\text{ digits}}.$$ Source language discrepancy: the Vietnamese wording says the 101st digit, rather than the 101-digit number.