In Canasta the card values do not correspond directly with the numbers shown on them.

The natural cards are valued as follows:

Aces: 20 points
4 to 7: 5 points
8 to King: 10 points

Jokers are worth 50 points and the Twos are worth 20 points (wild cards). The Black Threes (block cards) are worth 5 points. The Red Threes are worth 100 points.

At the end of a round (after a player "goes out"), the scores are calculated as follows:

Melds: The total points of the cards in your melds on the table
Hand: The total points of the cards in your hand
Going out: 300 points
Natural Canasta: 500 points
Mixed Canasta: 300 points
Red Threes: 100 points per red three, 800 points for all. If melds are not placed on the table, the points are turned into negative points (up to a maximum of 400 points).

The remaining cards in each player's hand are also taken into consideration using the point values above but are scored as negative points.