Posted in Early Reader, Non-Fiction, picture books

A math concept book with NO WRONG ANSWERS? Sign me up!

Which One Doesn’t Belong? Playing with Shapes, by Christopher Danielson, (Feb. 2019, Charlesbridge), $15.99, ISBN: 9781580899444

Ages 4-8

Math educator Christopher Danielson came up with a creative new way to get kids thinking about mathematical concepts: give them groups of shapes, and ask them, “What doesn’t belong?” The best part: NO WRONG ANSWERS. As the beginning explanation details, it’s all about the process, about critical thinking. One color could be different. A shape could be more squished, smooshed, or just look weirder than the others. It’s all in the eye, the mind, of the beholder here! Spreads alternate between layouts with shapes, and explanations on how every answer is correct, with supporting information like shapes, color, and other properties.

This is such a great way to make mathematics accessible to readers (kids and adults alike!). It doesn’t discourage anyone; it doesn’t make anyone’s answer, or rationale, wrong. Which One Doesn’t Belong shows readers how easy it is to approach things in a mathematical way: and this is coming from the lady who tells kids “the best way to do well in math is to not ask me for help with it”. Like the author himself says, “All properties count here; all ideas matter…”. Add this one to your nonfiction collections, build some programs around it for different age groups, and start making math more friendly to your readers!

Which One Doesn’t Belong? has a starred review from Kirkus and is the Winner of the Mathical Book Prize.


I'm a mom, a children's librarian, bibliophile, and obsessive knitter. I'm a pop culture junkie and a proud nerd, and favorite reads usually fall into Sci-Fi/Fantasy. I review comics and graphic novels at WhatchaReading ( I'm also the co-founder of On Wednesdays We Wear Capes (, where I discuss pop culture and geek fandom from a female point of view.

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