Method : 9's complement subtraction steps :
1. At first, find 9's complement of the B(subtrahend).
2. Then add it to the A(minuend).
3. If the final carry over of the sum is 1, then it is dropped and 1 is added to the result.
4. If there is no carry over, then 9's complement of the sum is the final result and it is negative.
1. Find Subtraction of 470 and 231 using 9's complement method
Here A = 470, B = 231.
Find A - B = ? using 9's complement
First find 9's complement of B = 231
Note : 9's complement of a number is obtained by subtracting all bits from 999.
9's complement of 231 is
Now Add this 9's complement of B to A
Hints : (Move mouse over the steps for detail calculation highlight)
Step-1
`=0+8`
`=8`
`:.` Sum`=8` | Step-2
`=7+6`
`=13`
`:.` Sum`=3` and carry`=1` |
Step-3
`=1+4+7`
`=12`
`:.` Sum`=2` and carry`=1` | |
The left most bit of the result is called carry and add it to the rest part of the result 238.
So answer is 239
2. Find Subtraction of 670 and 831 using 9's complement method
Here A = 670, B = 831.
Find A - B = ? using 9's complement
First find 9's complement of B = 831
Note : 9's complement of a number is obtained by subtracting all bits from 999.
9's complement of 831 is
Now Add this 9's complement of B to A
Hints : (Move mouse over the steps for detail calculation highlight)
Step-1
`=0+8`
`=8`
`:.` Sum`=8` | Step-2
`=7+6`
`=13`
`:.` Sum`=3` and carry`=1` |
Step-3
`=1+6+1`
`=8`
`:.` Sum`=8` | |
Here there is no carry, answer is - (9's complement of the sum obtained 838)
Note : 9's complement of a number is obtained by subtracting all bits from 999.
9's complement of 838 is
So answer is -161
This material is intended as a summary. Use your textbook for detail explanation.
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