As the total odd numbers from 1 to 100 is 50 and the total even number is 50. The probability of get an odd number and the probability of get an even number is the same:
[tex]\begin{gathered} P(\text{odd)}=\frac{50}{100}=\frac{1}{2}=0.5 \\ \\ P(\text{even)}=\frac{50}{100}=\frac{1}{2}=0.5 \end{gathered}[/tex]Then, the expected is a probability of 50% $19 and a probability of 50% $0