# 2018 Summer Game #10: Short Chain Subtraction

There are many variations of the chain games and our family has played most of them as solitaire games. Nicholas, Chiara, and Ian played Short Chain Subtraction today, game S18 in the Math Card Games book, and had a great time! This variation is a great family game and is best for two to three players.

You need six of each of the following basic number cards: 1s, 3s, 7s, and 9s. You also need three of each these basic number cards: 2s, 4s, 6s, and 8s. The columns for this chain game must begin with certain numbers, so provide a piece of paper showing the required numbers. Here they are.

Shuffle the deck and deal all of the cards face down evenly to everyone. Each player picks up the top four cards from his deck. During each turn, the player may play as many of the four cards as possible.

Here Nicholas played 1, 9, 7 and 4, as identified by our starting numbers. He then replenished his hand from his stack so he had four again in his hand.

Next Chiara played a 3 in the second column and a 3 on the 4 in the fourth column because 7 – 4 = 3. See how we’re taking the top two numbers, subtracting them, then laying down the card with the answer?

On Ian’s turn, he played a 2 on the 1 and a 9 on the 2.

How did he know what number to play on the 2? When looking at the two most recent cards in a column, you can assume a 1 in the tens place when the number on the last card is more than the one above it. So, in this case the 1 becomes an 11 and 11 – 2 = 9.

As play continued, the kids will know a column is complete when the first and last cards are the same. No more cards are added to that completed column.

Toward the end of the game, Nicholas had only one card left but Chiara had four and Ian had two. Sure enough, Nicholas won when he played that last card! Note that not all the columns must be complete in order to end the game. The game is over when someone is out of cards!

As you get comfortable with the game, you can make strategic decisions based on what cards will be needed a few plays ahead. Nicholas is pretty good at that. We’re off to play another round!

Looking for a solitaire option? Short Chain Subtraction Solitaire, game S19 in the Math Card Games book, makes for a fun solo challenge. The cards and starting numbers are the same as above. Deal all of the cards in fans of 3, face up.

Only the top card of each fan can be played, so look ahead when you have choices. The last card in any column can be moved to another column if you wish. If you get stuck, you may reshuffle the remaining cards once and lay out new fans.

Here, Peter played a 7 on the 6 in the last column, which freed a 9 to be played in the first column. This was followed by the 8 and 1, which closed out the first column.

Then Peter played the 2 on the 1 followed by the 9 in the third column, closing that column out as well.

Here is Peter’s successfully completed columns! Way to go!