How to add two two-digit numbers
   (for example 35 + 43).

    Place one number above the other number so that the tens' place digits and ones' place digits are lined up.     Draw a line under the bottom number.

              35
              43
             ___

    Add the two ones' place digits (5 + 3 = 8).

              35
              43
             ___
                8

     Add the numbers in the tens' place column (3 + 4 = 7) and place the answer below the line and to the left of      the ones' place sum.

               35
               43
              ___
               78