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## Card sums

By David, 18 February 2016 Activity

Mark the back of the royal cards with either +, –, ÷ or x.

Practice your sums with this fun card game.

### You will need

• A cheap deck of cards
• Permanent marker
• Someone to play with
• Calculators for checking (optional)

### Making the deck

1. Put the marked cards into four piles, one for each operation.

Go through the deck of cards, and take out all the 10s, jacks, queens, kings and jokers. Put these cards aside for now.
2. Use the marker to cross out all the ‘A’s on the aces. Replace each A with a ‘1’. Once the ink is dry, put the aces back with the other number cards. These cards are now your main deck.
3. Take all the royal cards you set aside earlier. On the back of each card, draw a symbol: either +, –, ÷ or x. Make sure you get a good mix of operations. Put these into four piles, one for each operation.

### Playing the game

1. Try to make a sum equal to the two-digit target number.

Deal each player a hand of seven cards from the main deck of number cards.
2. Deal two cards face up to make a two-digit number, known as the target.
3. Both players try to make a sum equal to the target number at the same time. They can use the numbers they have in their hand, and as many operations cards as they need.
4. When one player has an answer, yell ‘done’. The other player can check to see if the answer is right. First correct answer wins the round.
5. If neither of you can find a solution, deal yourselves two extra cards each and continue looking.
6. At the end of the round, put the operation cards back in their piles and shuffle all the number cards together. Then deal new hands and a new target.

### Extra rules you can try

• If you want a slower game, wait until both players have an answer. The winner is the player who used the most number cards in their sum.
• Every time you lose a round, you receive one fewer card in your hand at the start of the next round. When you’ve only got one card in your hand, you lose!
• Cut up some pieces of paper and write new operations on them. You could try +1 or x2 cards, or more advanced mathematicians could try square root or exponentiation cards.

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