Chapter 2, Problem 40E

Program Plan Intro

Hexadecimal subtraction:

The rules for subtracting two hexadecimal numbers are given below:

• Read both the numbers to find the number of bits.
• If the number of bits in the first number is less than that of second number, then pad the required zeroes to the left side.
• Numbers are represented in bytes (1 byte = 8 bits).
• Align the number in correct order after padding. The hexadecimal number that is followed by a minus sign should be subtracted from the other hexadecimal number.

Explanation of Solution

b.

“9988 – AB”:

• Start with the numbers from right to left.
  • Subtract “B” from “8”. The equivalent hexadecimal value for “B” is “11”.
    • Here, “8” is less than “11”. Borrow “16” from adjacent left side and add it to “8”. Since the adjacent left side number is “8”, it becomes “7” after borrowing.
    • Add “16” to “8” and then subtract “11” which give “13” as the result. The equivalent hexadecimal digit for the number “13” is “D”. Hence write D to the result.
  • Subtract A from “7”. The equivalent hexadecimal value for “A” is “10”.
    • Here “7” is less than “10”...

Explanation of Solution

c.

“A9F8 – 1492”:

• Start with the numbers from right to left.
  • Subtract “8” from “2”. The equivalent hexadecimal digit for number “6” is “6”. Write “6” to the result.
  • Subtract “9” from “F”. The equivalent hexadecimal value for “F” is “15”.
    • Subtract “15” – “9” which gives “6”. The equivalent hexadecimal digit for the number “6” is “6”. Hence write “6” to the result.
  • Subtract “4” from “9”. The equivalent hexadecimal value for number “5” is “5”...