He went in with $1M, odds of 50/50 and a 20% discount once the losses are over $0.5M. Lets assume for simplicity that all hands he plays are equal ($0.1M according to the article)
Because the discount kicks in at $0.5M of losses, he should plan to lose bets for $0.5M first. This is a setup.
Now he needs play to win the bets for remaining $0.5M he has.
Because the odds are 50/50, after a few rounds of playing with the $0.5M he has, he's going to have lost half the hands, and won half of them. While he gets 2x for his wins, he gives up only 0.8x for his losses.
Net = 2x - 0.8x = 1.2x. He just had to rinse and repeat with the $0.5M he was left with. Though I'm sure he brought in a lot more money once the $0.5M loss kicked in the discount.
Just note that this explanation is a simplification. 50/50 odds (technically 49.75/50.25 according to Johnson) have to be accompanied by an even performance on double-downs and splits.
Because the discount kicks in at $0.5M of losses, he should plan to lose bets for $0.5M first. This is a setup.
Now he needs play to win the bets for remaining $0.5M he has.
Because the odds are 50/50, after a few rounds of playing with the $0.5M he has, he's going to have lost half the hands, and won half of them. While he gets 2x for his wins, he gives up only 0.8x for his losses.
Net = 2x - 0.8x = 1.2x. He just had to rinse and repeat with the $0.5M he was left with. Though I'm sure he brought in a lot more money once the $0.5M loss kicked in the discount.
Just note that this explanation is a simplification. 50/50 odds (technically 49.75/50.25 according to Johnson) have to be accompanied by an even performance on double-downs and splits.