fill in the blanks on the pattern 98,97,95,92,88 ? ?

Answers are: 83 and 77

Notice how...
The jump from 98 to 97 is a decrease of 1
The jump from 97 to 95 is a decrease of 2
The jump from 95 to 92 is a decrease of 3
The jump from 92 to 88 is a decrease of 4

The pattern of decreases so far is: 1, 2, 3, 4

So the next decrease is 5
88-5 = 83

And the decrease after that is 6
83-6 = 77