4. Find Subtraction of 2870 and 1943 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 = 2870, B = 1943.
Find A - B = ? using 10's complement
First find 10's complement of B = 1943


Step-1: 9's complement of 1943 is obtained by subtracting each digit from 9

	9	9	9	9
-	1	9	4	3
	8	0	5	6

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Step-2: Now add 1 :
8056 + 1 = 8057

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Step-3: Now Add this 8057 to 2870

		1
	2	8	7	0
+	8	0	5	7
1	0	9	2	7

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Step by step solution of 2870 + 8057 = 10927

Write the numbers, so that each digit lines up vertically

	2	8	7	0
+	8	0	5	7

Step-1 :
`=0+7`
`=7`
Write the 7 in the sum place

	2	8	7	0
+	8	0	5	7
				7

Step-2 :
`=7+5`
`=12`
Write the 2 in the sum place and carry the 1 to the next carry place

		1
	2	8	7	0
+	8	0	5	7
			2	7

Step-3 :
`=1+8+0`
`=9`
Write the 9 in the sum place

		1
	2	8	7	0
+	8	0	5	7
		9	2	7

Step-4 :
`=2+8`
`=10`
Write the 10 in the sum place

		1
	2	8	7	0
+	8	0	5	7
1	0	9	2	7

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The left most bit of the result (10927) is 1, called carry and it is ignored.

So answer is 0927

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