Asks how many times something occurred or will occur (how many times).
その映画を何回見ましたか？
How many times have you watched that movie?
彼は何回も同じミスを繰り返した。
He repeated the same mistake many times.
この問題を解くのに何回練習が必要ですか？
How many times do you need to practice to solve this problem?