I Need your help with the maths homework?

Question

Need your help with the maths homework.

The sequence is 99, 90, 63, …, 55, 54.

Answer (a) 61 ,(b) 60 ,(c) 59 ,(d) 58

What is the missing number and why?

Answer 1

58

i dunno why but it minuses 7 then 5 the 3 then 1

Answer 2

I'm not sure, but it could be 58, because it's like -5, -3, -1