Akpos, Principal and Aunty Susan

Aunty Susan was having a problem with Akpos in her class.
Akpos said 'M'am, I should be in SS3, i'm smarter than my friend Musa and he's in SS3'.
Aunty Susan had heard enough of Akpos' complains & took him to the Principal's office.
She explained everything to the Principal who decided to test Akpos with some questions that an SS3 Student should know.
PRINCIPAL : What's 3+3?
AKPOS : 6
PRINCIPAL : 6+6?
AKPOS : 12.
And so on.
The Principal asked Akpos many questions and he got them right