how possible that which i can see the "date of month of 1986"?

Answer 1

Not sure what your question is, but here is a formula to calculate the number of days between two dates (from which you can find the "day"):
n1 = Y1 x 365.25 + M1 x 30.6 + D1
n2 = Y2 x 365.25 + M2 x 30.6 + D2
n1 - n2 gives you the number of days between the two dates.
Divide by 7, extrapolate with a known day, and you get the day of any date (down to 400ad, where the calender was changed).

Answer 2

What is your question - it is akin to asking what flavour is black.