Step 1: Write 124-28 into the subtraction vertical line. As shown in the figure:

Step 2: Since 4-8 is less than 0, borrow one bit from the minuend (that is, "2" in the decimal number) to become 14-8, and write vertically. As shown in the figure:

Step 3: Because two of the ten digits are borrowed by single digits, 1 remains. Since 1-2 is less than 0, one bit borrowed from the minuend (that is, "1" of the hundredth bit) becomes 1 1-2, and the result is 9, which is written vertically. As shown in the figure:

Step 4: Because the 1 of 100 is borrowed by one of 10, there is still 0 left. As shown in the figure:

Fifth: remove the highest order 0 and get the result. Namely: 124-28=96. As shown in the figure:

Subtraction by abdication, a special mathematical term, can also be called subtraction by borrowing. That is, when two numbers are subtracted and the number of digits to be subtracted is not enough, borrowing the previous digit is equivalent to adding 10 to this digit, and then calculating.