On February 5, 1998, it was Thursday. The day of the week on February 5, 1997, was

Wednesday

In calendar chapter there is a concept of odd days which can be explained as follows:

Odd days are the number of days more than the complete weeks in a given time period. Thus 12 days will comprise of 5 odd days.

For example: 1st January = Monday, then what will be on 9th January.