Math playing cards

I created a deck of cards. Each deck has the numbers 0 to 12 - 4 cards each.

I use these to play "WAR" but you can really use this for anything.

I printed 16 sets of cards - each set on a different color of cardstock. I laminated then cut out the individual cards.

At the beginning of the game the students pair up and divide the cards - FACE DOWN between them. On the count of 3 each student flips a card and the first student to multiply the cards and call out the correct answer wins the cards.
If both students call out the answer at the same time we have a WAR situation - they flip over the next cards and the first person to call out the correct answer wins all 4 cards.
Winner of the game has the most cards.