My daughter is obsessed with Hatchimal Colleggtibles. Ob. Sessed. She can recite the ones she has in alphabetical order (backward, even) as well as in the order in which they came into our house. She has studied the papers for them so much, she could probably close her eyes and draw an accurate map of their mythical land Hatchtopia.
If you don’t know what these toys are, I describe them as being just like baseball cards except they look like wee cute animal figures. The toys come in eggs that give only a subtle clue as to what’s inside (the speckles tell you what region the animal is from—if you want to know which colors map to which regions, ask my daughter). But there are common ones, rare ones, ultra-rare ones, and limited editions. Each year they release a new season, so you get to buy even more.
This post is not about extolling Hatchimals, however. Your kid may or may not obsess about them.
But they may very well obsess about something because that’s what kids do. We’ve realized that that obsession is a way to add one of our favorite obsessions as parents—talking about math all the time. Take all that child-level enthusiasm for a subject, weave in math, and end up with a winning combination.
Here are just some of the ways our whole family plays number games with her collection. Most of these naturally map well to physical collections, but you can probably figure out how to work math into more abstract obsessions. Compare dinosaur sizes, count the cars in a train, figure out how many dolphins can fit into a whale, and so on.
- Counting – This is one even little kids can do. Count the numbers you know, and then talk about how to go beyond.
- Counting By … – Group the collection into 2s, 5s, or 10s. And then count by that number.
- Attributes – Group the collection by different aspects. For Hatchimals, you could use the region they live in; whether their eyes are open, closed, or winking; the color of their wings; and more.
- More and Less – Are there more Season 3 Hatchimals in your collection or more Season 4?
- Addition and Subtraction – If you have 38 Hatchimals and buy one of the 5-packs, how many will you have? What if two of those are duplicates? If you take away all the Season 3 Hatchimals from your collection, how many are left?
- Multiplication and Division – If you have four sets of twins, how many twins do you have? If you divide your collection into groups of four, how many groups do you get and how many are left over?
- Money – If you get a certain amount each week for allowance, how long before you can afford a Hatchimal two-pack?
- Statistics – How many commons do you have relative to rares? What does that tell you about how many commons there are relative to rares in the whole population? You can even talk about sampling bias: If the only Hatchimals you’ve seen have open eyes, you might assume all Hatchimals have open eyes.
- Probability – If you’re buying a Unikeet pack, and you already have four out of twelve Unikeets, how likely is it that your next Unikeet pack won’t have any duplicates? This is also a good time to explain what “odds” actually means (which varies from most people’s understanding: 1:2 odds means you have a 33 percent chance of the outcome you want, not fifty percent).
- Data Visualization – Line up all your pink Hatchimals, your blue Hatchimals, and so on. That’s a graph of how many you’ve got in each color. Create a table with one set of attributes on the top and another set of attributes on the left. How many Hatchimals go into each cell?
- Mix and match – If you take away the four sets of twins from the total, how many non-twins do you have?
Talking about the numbers behind her collection has led to lots of fun math problems. How do you incorporate math into your children’s obsessions? We’d love to hear in the comments.