Question

If ‘a’ and ‘b’ are two integers and the sum of successor of ‘a’ and predecessor of ‘b’ is subtracted from the sum of predecessor of ‘a’ and successor of ‘b’ the result is equal to

Answer 1

$Given \: 'a' \: and \: 'b' \: are \: two \: integers$

$i) Successor \: of \: 'a' = ( a + 1 )$

$ii) Prodecesser \: of \: 'b' = ( b - 1 )$

$iii) Prodecesser \: of \: 'a' = ( a - 1 )$

$iv) Successor \: of \: 'b' = ( b + 1 )$

/* According to the problem given */

$\red { Sum \: of \: successor \: of \: 'a'\: and }\\\red{ predecessor\: of\: 'b' \:is \:subtracted\: from}\\\red{ the\: sum\: of \:predecessor\: of\: 'a'\: and}\\\red{ successor\: of\: 'b'}$

$= [ (a-1)+(b+1)] - [(a+1)+(b-1)] \\= ( a - 1 + b +1 ) - ( a + 1 + b -1 ) \\=\cancel { (a + b ) }- \cancel {( a + b ) }\\ \green {= 0 }$

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Answer 2

Answer:

B4 solving, see these two points:-

Successor is that number which one more than the actual number.

Predecessor is that number which is 1 less than actual number.

So, 

Successor of -1

= -1 +1 = 0.

Predecessor of -1

= -1-1 = -2.

Sum of successor and predecessor 

= 0 + (-2)  = -2.

Hence, the sum of successor and predecessor of -1 is -2.