Subtracting numbers in which the operands are greater than 9 can be more difficult to do without a piece of paper to work out the problem. When subtracting numbers greater than 9 it is best to start out by lining up the numbers so that the place values match up vertically.
Example:
36
-25
Starting with the one's column, subtract the numbers, in this case 6-5:
36
-25
1
Next subtract the bottom number in the tens column from the top number; in this case 3-2:
36
-25
11
Finally you arrive at your answer of 11.