_{The sum will be even when; both numbers are either even or odd,}

_{i.e. for both numbers to be even, the total cases} ⁵C₁X⁴C₁ (Both the numbers are odd)+⁴C₁X³C₁ (Both the numbers are even)= 32

_{The favourable number of cases will be,}

_{Both odd, i.e. selecting numbers from 1, 3, 5, 7, or 9, i.e.}

_⁵C1X⁴C₁ = 20

_{Thus, the probability that both numbers are odd will be =}

=

⇒