How to subtract two-digit numbers (for example 67 - 45).

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

  67
  45
  

• Subtract the bottom ones' place digit (5) from the top ones' place digit (7) and place the difference (2) below the line in the ones' place column.

  67
  45
   2
  

• Subtract the bottom tens' place digit (4) from the top tens' place digit (6). Place the difference (2) below the line in the tens' place column.

  67
  45
  22