Probability of an event
For the number to be same when seen upside down:

It can only contain either 0,1,8,6,9.

For first and last digit :
For it to be a 6 digit number first digit and the last digit cannot be 0.
If first digit is 6 then last should be 9 and vice-versa.
If first digit is other than 6 or 9 (ie. 1,8) then they both should have same digit.

For second and fifth digit / For third and fourth digit :
If first digit is 6 then last should be 9 and vice-versa.
If first digit is other than 6 or 9 (ie. 1,8) then they both should have same digit.


Total Number of 6 digit numbers = 9 * 10 * 10 * 10 * 10 * 10  ([9] as first digit cannot be 0)
Numerator = 4 * 5 * 5 ([4] as first and last digit cant be 0)
So,
Probability should be = Numerator / Total number of 6  digit numbers