The meaning of expected value

Say in a game of roulette, there are 37 numbers, 0 to 36.
The casino payout is 35:1 for winning no.
The odd of winning is 1/37.
The odd of losing is therefor 36/37.
EV = 1/37 x ($35) + 36/37 x ($1)
= - 0.027

Hence, we say the expected value to us is -$0.027