In 500 Rummy every card you lay down scores for you and every card you are caught holding counts against you. At the end of each hand, add up your melds, subtract what is left in your hand, and write the result in your hand column; it can be negative. Tens and face cards are worth ten.
Aces and the low cards are where tables differ, so the sheet has a line to write your table's values before you start. In Cards Royale the Competitive preset counts an ace five and the rest by their pips, while house rules count aces fifteen and twos to nines five each. The game ends after a hand in which one player alone holds the top score at five hundred or more.
At other tables
The rules on pagat.com count an ace fifteen, or one when it is melded low in ace, two, three, and the other cards at face value. Source: pagat.com
This is how Cards Royale scores 500 Rummy. The full rules are on the how to play 500 Rummy page.