The second problem is: +81 - 9 = 72

Solution:

This problem involves subtraction. We subtract 9 from 81. To do this, we can think of it as borrowing from the tens place if needed. In this case, 11 - 9 = 2, and we have 7 in the tens place, so the answer is 72.

 81
- 9
--- 
 72

Answer: 72