Method : 8's complement subtraction steps :
1. At first, find 8'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 the result is positive.
4. If there is no carry over, then 8's complement of the sum is the final result and it is negative.

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1. Find Subtraction of 402 and 314 using 8's complement

Solution:

8's complement subtraction steps :

1. At first, find 8'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 the result is positive.
4. If there is no carry over, then 8's complement of the sum is the final result and it is negative.

Here A = 402, B = 314.
Find A - B = ? using 8's complement
First find 8's complement of B = 314


Step-1: 7's complement of 314 is obtained by subtracting each digit from 7

	7	7	7
-	3	1	4
	4	6	3

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Step-2: Now add 1 :
463 + 1 = 464

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Step-3: Now Add this 464 to 402

	4	0	2
+	4	6	4
1	0	6	6

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Step by step solution of 402 + 464 = 1066

Write the numbers, so that each digit lines up vertically

	4	0	2
+	4	6	4

Step-1 :
`=2_8+4_8`
`=2_10+4_10`
`=6_10`
`=6_8`
Write the 6 in the sum place

	4	0	2
+	4	6	4
			6

Step-2 :
`=0_8+6_8`
`=0_10+6_10`
`=6_10`
`=6_8`
Write the 6 in the sum place

	4	0	2
+	4	6	4
		6	6

Step-3 :
`=4_8+4_8`
`=4_10+4_10`
`=8_10`
`=8xx1+0`
`=10_8`
Write the 10 in the sum place

	4	0	2
+	4	6	4
1	0	6	6

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The left most bit of the result (1066) is 1, called carry and it is ignored.

So answer is 066

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