Method : 8's complement of a number is 1 added to it's 7's complement number.

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1. Find 8's complement of 402

Solution:


Step-1: 7's complement of 402 is obtained by subtracting each digit from 7

	7	7	7
-	4	0	2
	3	7	5

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Step-2: Now add 1 :
375 + 1 = 376

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So 8's complement of 402 is 376

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2. Find 8's complement of 342

Solution:


Step-1: 7's complement of 342 is obtained by subtracting each digit from 7

	7	7	7
-	3	4	2
	4	3	5

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Step-2: Now add 1 :
435 + 1 = 436

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So 8's complement of 342 is 436

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3. Find 8's complement of 465

Solution:


Step-1: 7's complement of 465 is obtained by subtracting each digit from 7

	7	7	7
-	4	6	5
	3	1	2

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Step-2: Now add 1 :
312 + 1 = 313

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So 8's complement of 465 is 313

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4. Find 8's complement of 1256

Solution:


Step-1: 7's complement of 1256 is obtained by subtracting each digit from 7

	7	7	7	7
-	1	2	5	6
	6	5	2	1

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Step-2: Now add 1 :
6521 + 1 = 6522

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So 8's complement of 1256 is 6522

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5. Find 8's complement of 31421

Solution:


Step-1: 7's complement of 31421 is obtained by subtracting each digit from 7

	7	7	7	7	7
-	3	1	4	2	1
	4	6	3	5	6

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Step-2: Now add 1 :
46356 + 1 = 46357

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So 8's complement of 31421 is 46357

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