Christopher had a bunch of friends over for a day of sled riding and snowball fighting. At different times throughout the day, the friends took a break and went inside to warm up. Christopher's mom had cocoa mix and hot water waiting for them each time. To make a mug of hot chocolate, the kids needed to add 1 cup of hot water; however, they got tired of waiting for their turn to use the 1 cup measuring cup. So instead, they experimented the other measuring cups: 1/2, 1/3, 1/4 and 1/8.

Challenge: How many different ways were they able to make 1 cup using the other measuring cups?

If possible, use your own set of measuring cups and experiment. Consider the following questions:

• Which measuring cup is difficult to combine with the others? why?
• How could you organize your data to make sure you've found all of the possible combinations of measuring cups?
• Do you seem to use one measuring cup most often? why do you think that is?
• What other measuring cups might be useful to have?
• What if you needed 2 cups of hot water? which combinations of measurements might be useful?

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