Answer: 0
Explanation:
IF we think about it, we ned to realize that the only two numbers that would possible give us a four digit number (PART) are 0 and 1. (All other options give us fire digit number after numliplying by 9). Then we must remmember that each digit has to be a different digit. So, if we put 1 in the place of R, we would have to put 2 in the place of T because we can not use numbers twice. Therefore, the only solution would be if it is o.