Adding 2 digit numbers - with Carrying:

     45
  + 67
 --------
 
 
Step #1):

    * Add the 5 and 7 to get 12.
    * Since 12 is greater than 9, you'll have to carry the 1.

     1
     45
  + 67
 --------
       2

Step #2):

    * Add the 4 and 6 to get 10.
    * Add the carried 1 to get 11.
    * 11 is greater than 9, but there are no more digits to carry over, so just write the 11 down in front.

 1 1
    45
  +67
 --------
  112
  
The answer is: 45 + 65 = 112