We’ve been having some fun exploring measurement and estimation around here lately. Estimation is an important math concept that I think is often overlooked or glazed over, but it’s an invaluable real life skill. Not only is it helpful in all sorts of real life situations to be able to estimate sizes, costs, and amounts, but it is also helpful as students get into higher level math. After spending a significant amount of time working out an algebra problem, it’s essential that students be able to estimate to confirm whether or not their answer makes sense. To help my kids start to get an idea of estimation and help increase spatial reasoning skills, I’ve created a printable Gumball Estimation Activity, and I hope you will enjoy it too!
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This free printable pack includes a gumball machine (in color and black and white) as well as 3 different sizes of gumballs to print and cut out. There is also a recording page with some questions for students to answer as they try to estimate how many gumballs of each size will fit. I laminated our gumball machine page because I’m sure we’ll use it again and again for all sorts of different activities, but you certainly don’t have to.
It’s up to you how you will use it, and how your students might go about making reasonable estimates, but I would encourage you to not give too much guidance. Simply have them cut a few out and make their estimates.
Be sure it’s clear up front, however, that gumballs cannot overlap. Otherwise, they could fit all the gumballs on the page somewhere. 😉
Ask good questions, such as, “How did you come up with that number?” or “If your estimate was too large (or small) why do you think that is? How could you make a better estimate next time?”
As they move onto the medium and small sizes of gumballs, ask them if more or less gumballs are going to fit. See if they base their estimates on how the medium compares to the large, or if they simply try use the same method they did with the large gumballs.
If a particular estimate is far from correct, ask them to go back and look for a different approach that might provide a more accurate count (knowing, obviously, that we’re not going for exact, just close).
When they’ve finished, here are some questions for further discussion and consideration (depending on the age of your students):
- Which size of gumball fits the best in the gumball machine (meaning it leaves the least amount of space)?
- If you’re trying to get an accurate count to fill up your gumball machine, is it better to have an estimate that is too high or too low? Why?
- Can you determine the total surface area of all the gumballs in the machine? How much surface area is left empty with each of the 3 sizes of gumballs?
- If you are selling the gumballs in the machine, what size gumball is going to make you the most money? Why?
And then, if your students enjoy this, increase the challenge by filling an actual gumball machine (or large jar) and having an estimation challenge! See who can come closest to the correct number, and then have them explain their method of estimation.
I hope you enjoy these free printables! And if you’re looking for another engaging way to practice measurement and estimation, try wrapping up in toilet paper like a mummy! Kids think this is GREAT fun! 🙂
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