Example of subtraction:
Subtract 78 from 136.
While subtracting the units column, 6 - 8, a 10 that is borrowed from the tens column. This now creates subtracting the units column 16 - 8. An 8 is placed under the units column. Further the tens column is subtracted.
A 10 was borrowed from the tens column and now 7 is subtracted from 12, not 13. This yields: 12 - 7 = 5. The 5 is placed under the tens column and the difference is 58.
This could be completed for any subtraction formula. While the digit in the subtrahend column is larger than the digit in the minuend in the similar column, a number from the further higher place position column is "borrowed." That reduces the higher position column by one.
Subtraction can be verified through adding the difference to the subtrahend that should result in the minuend.