Build the greatest number less than 700 that has 9 in the tens place and different digits in each of the other places

explain how you choose the digits

I think the greatest number less than 700 with 9 in the tens place and different digits in each of the other places is 698.
I chose 6 to be in the one of hundreds place because it is the greatest number that is less than 7 in the hundreds place. I also chose 8 to be in the ones place because it is different from 6 and 9 and the greatest number in the ones place that is not 9.

699, because it has 9 in the tens place and 9 in the ones would be the greatest number there, and 6 in the tens, because it has to be less than 700.