The abilities of Frederick Algernon Trotteville

[Wolfgang]

Not to mention the languages no one else speaks (vanishing prince).

[Barnard]

I’ve wanted to say this before,
and now is the time, I am sure.
Fatty has talents,
but I think, on balance,
some of his pomes are quite pore.

[Katharine]

Very good.

[Lucky Star]

Ventriloquism comes in very handy for him in Strange Bundle.

[Ian]

I think that it's noticeable that in the later books, he seems (usually) to be less boastful and more empathetic to what others may think and a much more likable and caring character. In Burnt Cottage he comes across as a rather spoilt brat!

[Hannah]

He's also champion in eating the most cakes and macaroons

[Blytonfan]

Being kind to Bets and not ignoring or treating her as a pest.

[Susie9598]

Isn’t he - along with Eunice- a chess champion? In Missing Man, they settle down to play chess, and Mr Trotteville watches them, saying “ah, two school champions.”

[pete9012S]

Brilliant Susie!
I had completely forgotten about that. I think this is the only book that mentions chess?

Missing Man:
And so, when Eunice, who seemed to have forgotten that she had been offended,
suggested after supper that they should have a game of chess, Fatty mournfully shook his
head.
‘Nothing I’d like better than to beat you at chess, Eunice,’ he said, ‘but . . .’
‘Beat me! You couldn’t!’ said Eunice. ‘I’m champion chess-player of my school!’
‘How strange—so am I,’ said Fatty, quite truthfully.

[Hannah]

Good for the male champion chess player that a little bit later the mouse appeared .