Numbers

[Bilko]

A) logically which number should replace the ? in this series 260 216 128 108 62 54 ? 27

B) which number when spelt out in full is the largest possible that does not use any letter twice

[kempie]

a) 29

[ontarioice]

B. Fivethousand ?

[mohill]

A. Tthere are two series here. The second, fourth, sixth and eighth numbers are formed by halving the preceding one in this series. (108 is half of 216, 54 is half of 128, and so on).
The other series, is formed by halving and then subtracting 2. (Half of 260 is 130; minus 2 gives 128, and so on)
Kempie, I hope you don't mind my addition to your solution,