THE SPANISH 'BARAJA'

The probability in mathematics is the extent to which an event is likely to occur, measured by the ratio of the favourable cases to the whole number of possible cases. One of the contexts in which the probability is very present is in the packs of card. I want to focus on the Spanish deck.

The Spanish deck is composed by forty cards (although there are other packs which have forty-eight), and they are classified in ten groups: gold, cup, sword and clubs. In each group the cards are the ace, two, three, four, five, six, seven, jack, horse and king.

There are a wide range of games to play with the Spanish deck, but in all of them the probability has an important role to decide the winner. When we have the whole pack of cards, there are some percentages to find a concrete card. For instance, the probability to take a gold card is 10/40 (ten are the favourable cases and forty possible cases); to take an ace, 4/40 (10%); to take a jack, horse or king, 12/40 (30%); to take any card, 1/40… As readers can see, the probability could be expressed in different ways: fractions, percentages, etc.

In my view, using the Spanish deck to introduce the probability is great for Primary children for two reasons: the majority of them know at least a game to play with the pack, and the manipulative material is always interesting to attract their attention; thus it would be positive to work it with learners.

A significant activity for any cycle could be developed with the previous cases that I have detailed in the previous paragraphs. It could add more complex calculations of probability. For example, only in swords group of cards, finding the probability to take a card with less than six words (the answer would be 5/10), or to take two cards whose value is 12 (the favourable cases would be the horse -a value of 11- + the ace, the jack -a value of 10- + the 2, and the 5 + the 7; the possible cases, 45; so the result would be 3/45).