9. Every asterisk in the equation $2 * 0 * 1 * 5 * 2 * 0 * 1 * 5 * 2 * 0 * 1 * 5=0$ is to be replaced with either + or - so that the equation is correct. What is the smallest number of asterisks that can be replaced with + ?
A 1
B 2
C 3
D 4
E 5
9. B The sum of the digits on the left-hand side of the equation is 24 . Hence the equation formed by inserting + and - signs must be equivalent to $12-12=0$. The smallest number of the given digits required to make 12 is three $(2+5+5)$. Therefore the smallest number of asterisks that can be replaced by + is two and they would be placed in front of two of the three 5 s.