Suppose you bet on every single number on the roulette wheel. You’d be guaranteed a win because you’ve covered all the numbers.
But you’d lose money.
The payout for a single number bet in roulette is 35 to 1, so you’d win 35 units on the bet you won.
But you’d lose 37 units on the 37 losing numbers, for a net loss of two units.
More About the House Edge in Roulette
It wouldn’t matter if you chose a different combination of bets, either. You could bet on red, bet on black, and place a single bet on each of the green numbers. You’d still see a net loss no matter where the ball landed.
If you bet on black and win, you lose the bets you had on red and the bets you had on each of the green numbers.
If you bet on red and win, you lose the bets you have on black and the bets you had on each of the green numbers.
If you bet on green and win, you still lose the bets you had on black and red and on the other green 0.
Repeat this often enough, and eventually, you’ll lose all your money.
The variation of roulette that I’ve been using for this example is called “American roulette.”
But it’s not the only variation of roulette in the world.