N4
何〜か
なん〜か
Some, Several, A few
そこには何回か行ったことがあると思う。
I think I have been there several times.
Explanation
'何 ＋ counter ＋ か' means 'some, a few': you can't give the exact number, but you know there are some, usually not many.
「何人か」 (a few people), 「何回か」 (a few times), 「いくつか」 (a few).
「何人かの学生が来た」 (A few students came).
Mixed up with
The 「か」 here is not a question: 「何人か」 means 'some people', not 'how many people?'.
As a subject it can go straight before the verb or take 「が」: 「何人かが来た」. Before a noun add 「の」: 「何人かの学生」.
「何回か」 is 'a few times'; 「何回も」 is 'many times', stressing how often.