Decimal Pickle

In our last class we played a game called Decimal Pickle.  All you need is a deck of cards with 10, Q, and K removed, and a pencil and paper!  It's very simple to set up-- draw a path of ten steps, you could use circles, arrows (like I did), or any shape you want.  The goal of the game is to create sort of a number line where you can place decimals in order on the path from 0 to 1.  The cards you flip over on your turn are the numbers you get to arrange to form a decimal to place on the path.  Red cards mean choose another card, up to three cards.  Black card means stop.  So for example I flip over a red Jack which represents 0, and a black 8 so I stop.  Now I have two possibilities for decimals: .08 or .80.  Since there are no blank arrows between .032 and .11 I cannot place .08 on my path.  However, .80 is greater than .789 and less than .938, therefore I can place .80 on my last blank arrow, and I win!  

A couple things to keep in mind, if you draw a decimal that is a repeat, say I draw a black 5 again, I cannot fill in two spaces with the same number.  Also if there's no space for the decimal I get I must pass on that turn, for instance if I draw a red 1, and a black 2, the only possibilities are .12 or .21 which would not fit between any existing arrows, so I pass.  

I think this is a great game to develop an understanding of decimal quantity.  I think it especially emphasizes quantity in terms of the decimal places.  For instance, it helps students learn that there's a big difference between .37 and .037 because each new decimal will have a context--it will have numbers less than and greater than the number.  I also think this could be a nice intuitive introduction to start learning inequalities and their symbols, or possibly review them if they had learned about them a bit in elementary.  

There is also a benefit in being a pair game because students can make mistakes in placements and the whole class won't notice, only their partner might.  So there's an aspect of not only knowing your game, but also checking to make sure your partner is playing correctly.  It provides lots of examples and nonexamples of appropriate placement of decimals and can involve all levels of understanding.  

For us college students it really helped try to break our habit of saying "point zero six seven" which really has no mathematical meaning and instead practice saying "sixty seven thousandths" which can help set the context of decimals as fractions of tenths, hundredths, or thousandths.  Pronouncing decimals as fractions can help students with the fluidity of switching between the different representations.  If a student was given the fraction 7/10 they would have a much easier time creating the decimal .7 if they were used to hearing .7 as seven tenths instead of point seven.  

There are some variations that can make the game more fun.  My partner and I decided to increase our paths to 15 spots so it would not only take longer to fill in, but it would also make it more difficult to know how to space the decimals.  Instead of having the strategy of putting .5 in the middle, you now no longer have an exact middle.  So in your first couple turns when you can place your decimals in any of the blank spaces, you have to think harder about what numbers could eventually go in the spaces you leave blank.

I love strategic games, and I think this is the perfect combination of a simple game concept that can really aid learning while still having enough strategy and variations to make it fun and exciting for all types of learners.