1. Find Subtraction of 470 and 231 using 10's complement

Solution:

10's complement subtraction steps :

1. At first, find 10'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 10's complement of the sum is the final result and it is negative.

Here A = 470, B = 231.
Find A - B = ? using 10's complement
First find 10's complement of B = 231


Step-1: 9's complement of 231 is obtained by subtracting each digit from 9

	9	9	9
-	2	3	1
	7	6	8

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Step-2: Now add 1 :
768 + 1 = 769

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Step-3: Now Add this 769 to 470

	1
	4	7	0
+	7	6	9
1	2	3	9

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Step by step solution of 470 + 769 = 1239

Write the numbers, so that each digit lines up vertically

	4	7	0
+	7	6	9

Step-1 :
`=0+9`
`=9`
Write the 9 in the sum place

	4	7	0
+	7	6	9
			9

Step-2 :
`=7+6`
`=13`
Write the 3 in the sum place and carry the 1 to the next carry place

	1
	4	7	0
+	7	6	9
		3	9

Step-3 :
`=1+4+7`
`=12`
Write the 12 in the sum place

	1
	4	7	0
+	7	6	9
1	2	3	9

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The left most bit of the result (1239) is 1, called carry and it is ignored.

So answer is 239