$A$ student says that if you throw a die,it will show up $1$ or not $1$. Therefore,the probability of getting $1$ and the probability of getting 'not $1$' each is equal to $\frac{1}{2}$. Is this correct? Give reasons.

(B) No,this is not correct.
When a fair die is thrown,the total number of possible outcomes is $6$,which are ${1, 2, 3, 4, 5, 6}$.
The probability of getting $1$ is $P(1) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{1}{6}$.
The probability of getting 'not $1$' is $P(\text{not } 1) = 1 - P(1) = 1 - \frac{1}{6} = \frac{5}{6}$.
Since $\frac{1}{6} \neq \frac{5}{6}$,the student's claim that each probability is $\frac{1}{2}$ is incorrect.