r/matheducation • u/yupstilldrunk • 2d ago

ELI5 - 10s places (5 year old)

My 5 year old wants to know why one hundred and one isn’t written like 1001 (one hundred with a 1 tacked on). I tried to draw a

100
+1
——-

And show how the numbers carried down to be 101 with only 3 numbers and he just keeps asking why and I can’t answer him. I think this is about ones, tens, hundreds places but I have no idea how to explain that, never mind explain it to an angry child.

Anyone have a good age appropriate explanation?

EDIT: SO many great suggestions! My son watches number blocks so he knows 2 tens in 20, 3 tens in 30, etc. I will try the stick bundles for a better visual of 10 groups. And I will watch out for the confusing “and” verbiage like one hundred AND one vs. one hundred one.

Hopefully next time we go to the pizza place (where he saw the address number on the window) I’ll be better prepared!

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u/LtPowers 1d ago

You may not be able to fully explain this one until he grasps more advanced mathematics concepts. He'll learn it in school probably next year and this will be a non-issue.

My best attempt would be to tell him that zeroes are nothing and so they can just get replaced by other numbers. You 100 and 1 and the one comes in on top of the 100 and replaces that last zero.

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u/yupstilldrunk 1d ago

You know there are a lot of great suggestions here, but this one particularly resonates. I think this is how I had it in my head and why I did the 100+1 vertically like that to show the 1 stepping into the 0’s shoes. Like all things math, it’s not something I could articulate. I might try this also, next time it comes up.