tarjetas de fracciones
to play cards = jugar barajas
"Cards" in Spanish is "tarjetas." It is pronounced, "tar-HAY-tas." Sites such as learn-spanish.co.il provide audio pronunciations of many common Spanish words.
When you are talking about suits of cards, the word "diamante" is used.
Aceptan tarjetas Discovery?
"Spanish cards" would be "tarjetas españoles".
You say, "naipes de tarot," which means "cards of tarot." Another term that connotes 'cards' is "baraja de tarot", which means, "deck of tarot." "Jugar a barajas" means simply "to play cards." In Spanish, you don't put two nouns together and pretend that one modifies the other. It's usually really bad grammar.
The concept of "flash cards" i.e. index cards for memorizing material, not a glittery piece of paper, does not exist in Spanish. The best way to translate it would be to translate the concept: "Tarjetas de memorización" - "Cards for memorizing" "Tarjetas de destello" are cards that are flashy or bright (like the glittery piece of paper).
Spanish Christmas cards can be purchased in store at Walmart, Target, Kmart, and Hallmark stores. Spanish Christmas cards can also be purchased at those retail websites.
It is 26/52, a fraction which can be simplified.
Cards
It's called "Simplificación de fracciones" in some places, another name for fractions is "quebrados"
Sister in law in Spanish is cunada.