If the number 481 * 673 is completely divisible by 9, then the smallest whole number in place of * will be:
2
5
6
7
Explanation:
Sum of digits = (4 + 8 + 1 + x + 6 + 7 + 3) = (29 + x), which must be divisible by 9.
$\therefore$ $ x $ = 7.