1. Find Subtraction of 1B06 and 77C using 15's complement method

Here A = 1B06, B = 077C.
Find A - B = ? using 15's complement
First find 15's complement of B = 077C

Note : 15's complement of a number is obtained by subtracting all bits from FFFF.
15's complement of 077C is

	F	F	F	F
-	0	7	7	C
	F	8	8	3

Now Add this 15's complement of B to A

1	1
	1	B	0	6
+	F	8	8	3
1	1	3	8	9

Hints : (Move mouse over the steps for detail calculation highlight)

Step-1 `=6+3` `=6+3` `=9` `=16xx0+9` `=9_16` `:.` Sum`=9`	Step-2 `=0+8` `=0+8` `=8` `=16xx0+8` `=8_16` `:.` Sum`=8`
Step-3 `=B+8` `=11+8` `=19` `=16xx1+3` `=13_16` `:.` Sum`=3` and carry`=1`	Step-4 `=1+1+F` `=1+1+15` `=17` `=16xx1+1` `=11_16` `:.` Sum`=1` and carry`=1`

The left most bit of the result is called carry and add it to the rest part of the result 1389.

	1	3	8	9
+				1
	1	3	8	A

So answer is 138A