Verbal Reasoning - Mental Ability Questions

If 20 - 10 means 200, 8 / 4 means 12, 6x2 means 4, then

100 - 10 x 1000/ 1000 + 100 x 10 = ?

Select the related word/letters/numbers from the given alternatives:

LAMP : IXJM :: FISH : ?

Select the related word/letters/number from the given alternatives.

97 : 63 : : 67 : ?

Select the related word/letters/numbers from the given alternatives:

5 : 124 :: 7 : ?

Select the related word/letters/number from the given alternatives.

GROUPS : ITQWRU : : SECOND : ?

Select the related word/letters/number from the given alternatives.

72:90::156:?

Select the related word/letters/number from the given alternatives.

DR : KK : : LN : ?

Select the related number from the given alternatives.

39 : 52 :: 51 : ?