Answer :
There are two of them:
1). (n * a) means n + n + n + n + n + n + n + . . . 'a' times.
2). (n * a) also means a + a + a + a + a + a + a + a + . . . 'n' times.
1). (n * a) means n + n + n + n + n + n + n + . . . 'a' times.
2). (n * a) also means a + a + a + a + a + a + a + a + . . . 'n' times.