To ask “how many” use “E fia” when referring to anything other than people.
“How many earrings do you have?” — “E fia au tautaliga?” or “E fia tautaliga a oe?”

To ask “how many” people use “E to’afia”
“How many sisters do you have?” — “E to’afia ou uso?” or “E to’afia uso o oe?” (If you ask a girl–use “tuafafine” if asking a boy)

“How many teachers does he/she have?” — “E to’afia ana faiaoga?” or “E to’afia faiaoga a ia?”

To ask “how many per” place the word “ta’I” after the word “E”

How many hats do you two have?
How many hats do you two each have?

E fia pulou a oulua?
E ta’i fia pulou a oulua?

How many friends do you (all) have?
How many friends do each of you (all) have?

E to’afia uo a outou?
E ta’i to’afia uo a outou?

(remember to still use to’afia because you are asking how many people – friends. Just add ta’i in front because you want to know how many per person)

How many books per bag?
How many spoons per kitchen?

E ta’i fia tusi i le ato e tasi?
E ta’i fia sipuni i le umukuka e tasi?

(use “e tasi” to be more clear)

To respond use “E” followed by the amount
For people respond by saying “E to’a” followed by the amount

E fitu au apu
E lua o’u mata
E to’a valu ona fanau
E to’a fa ana faiaoga
E to’atele tagata i fafo.

You have seven apples
I have two eyes
He/she has eight children
He/she has four teachers
There are a lot of people outside