Chanakya Bhadra Paul, the question you typed is wrong but if you mean:
HOW MANY WHOLE NUMBERS ARE THERE BETWEEN LARGEST 6-DIGIT NUMBER AND SMALLEST 5-DIGIT NUMBER, than the answer is:-
Largest 6-digit number=999999
Smallest 5-digit number=10000
Wnos. between them =(999999-10000)-1
=989999-1
=989998
Hence 989998 whole nos. are there between LARGEST 6-DIGIT NUMBER AND SMALLEST 5-DIGIT NUMBER