No hint given.
What are the remainders when \(100\) and \(10\) are divided by \(7\)?
No hint given.
Try to find a condition on six-digit integers that detects divisibility by \(7\). There is a well-known general test for divisibility by \(7\), but it will be useful to find another one that is specific to six-digit integers and similar to the condition for three-digit integers implied by (b) and (c).