Math is Real Life: Party Planning

It's time for the March post of Math is Real Life, hosted by Jaime from Miss Math Dork.

This time, I'm sharing my math experiences regarding planning a First Birthday party for my son.  Specifically, I want to talk about the process I went through in order to make sure I had enough punch and water for everyone (capacity).

First, I had to think about how many people would be there.  There were 9 adults and 1 baby.

Then, I had to estimate about how much each person would drink.  I wanted to have MORE than enough, so I I purposefully estimated a little more than I really thought each person would drink.  I guessed that 4 cups would be enough for everyone.

Then, I had to multiply the number of cups by the number of adults (4 x 9 = 36).  So I needed at least 36 cups.

Next, I had to figure out how many cups are in a gallon. This is where I had to visualize my "King Gallon".

It helped me remember that there are 16 cups in a gallon.  If I need to provide 36 cups total, I would need 3 gallons of punch or water because 16 cups x 3 gallons would give me 48 cups, with 12 extra cups in case someone was extra thirsty. 

Finally, I was ready to make the punch and buy the gallons of water!

Do you have a saying or graphic that helps you remember the standard units of capacity?  I'd love to hear your ideas!