So dice sites like prime dice and bitvest have a house edge of 1%.
 
When the probability (win chance) is set to 50% everything seems to make sense with the house edge. With a 50% chance the win payout without a house edge is 2. When you apply the 1% house edge (2 * .99) you get your payout of 1.98 just like how it shows on all dice sites. But I can’t wrap my mind about what I am doing wrong when calculating the win payout for probabilities above 50%. For example when I set the probability to 51% on bitvest the win payout is 1.9411. How did they get this result. If I take the true payout without house edge of 1.98 and multiply it by .99 I get 1.9602.
 
I know I am doing something wrong because these payouts are on all dice sites so their math must be right. Can someone point me in the right direction, maybe explain with a proper equation?