It’s taken me longer than I would have liked to read this book (due to curriculum issues) but I’m
so glad I did! Very accessible, relatable characters, interesting problems to solve. My pupils actively investigated the problems from the book, possibly due to their interest in predicting what would happen next. I’m delighted to see that this is part of a series!

When FBI Special Agent Carlson accidentally texts a fifth grader to let him know he was kidnapped, he had no idea of his mistake. And most fifth graders wouldn’t know what to do with such a text. But Jordan Waters, with the help of his friends Justin, Stephanie, and Catherine. was no typical fifth-grader. They were The Math Kids, and they had helped the FBI before, using math to help solve the kidnapping of Catherine’s father and a cold-case bank robbery.

But this was different. Agent Carlson had been kidnapped, and they didn’t know any other FBI agents. They tried calling the agency, but there were too many agents for them to find the person they needed. Until some quick thinking by Justin, who realized that the agent’s last name was probably similar to his friend’s name, and that gave them the name of an agent would could help them, and more importantly, help Special Agent Carlson.

It’s not until they knew their FBI friend was safe that they found out what had happened—he had been doing research on a case in Cairo, Egypt, when he’s been captured. He was able to get away, but he was no closer to solving his case. A billionaire had gone missing. He was presumed dead, and if no one was able to figure out the riddles in his will, then all his money would go to his lawyer. The FBI agents knew that there was something strange going on, but they couldn’t figure out the riddles.

The will mentioned “the great triangle,” and Agent Carlson took that to mean the Great Pyramid, so he had gone to Egypt. But Catherine had been studying triangles, and she thought that the agent was on the wrong track. Her father had taught her a little about Blaise Pascal and the triangle he came up with that is full of patterns. She thinks that is the great triangle that the will referred to, and she thinks that the riddles will be solved by using Pascal’s triangle.

But they are up against a deadline. The Math Kids only have so much time to solve the riddles before the lawyer gets all the money. And when Agent Carlson’s kidnappers show up back here in D.C., they all realize just how dangerous this puzzle is, and how important it is that the good guys find the answers to the riddles first.

The Triangle Secret is the sixth in The Math Kids series, and this may be their biggest case yet. Author David Cole combines his years of mathematical learning and his years of teaching children into these books that use math puzzles to solve crimes. These kids are smart and honorable, and these stories show how math can come in handy in real life. There is even some extra information at the end of the book, about the abstract artist Catherine had been studying, about Beethoven, and about other unusual wills.

I enjoyed this book. This is the kind of book I would have loved as a (nerdy) kid. I would have found the puzzles really interesting (similar to Encyclopedia Brown, but with lots more math). But what I could have really enjoyed is reading about the friendships that these friends have built. They support each other, no matter what pastimes they’re pursuing, and they work together to find the answers. I don’t think these books are for any kid, but I think smart kids who are curious about the world and interested in finding answers to their questions and solving puzzles will find some friends with The Math Kids.

Egalleys for The Math Kids The Triangle Secret were provided by Common Deer Press through NetGalley, with many thanks.

.An interesting approach to maths. Learn through stories so it doesn't actually feel like a maths lesson.

Great story.

The triangle secret by David Cole.
The math kids book 6.
When FBI Special Agent Carlson is kidnapped in Egypt while investigating the plane crash of an eccentric billionaire inventor, Jordan and his friends spring into action. Catherine, The Math Kids must unravel the clues in Howell's mysterious will before its too late. If they can't figure out the secret of the triangle in time, Howell's money will be gone forever.Now the Egyptians are after the Math Kids, too. In their most exciting adventure to date, the four friends will need all their math skills to save their FBI friend and find the missing money.
A good read. Good story and characters . 3*.

My sister loves to read these books. They are fun and she always looks forward to reading the next chapter. They are also clever and make it interesting for kids.

If you have been following this series, you will love this one as well!

More suitable for young readers who love Math and for beginners who wants to start reading mystery books, I would say this is a perfect candidate.

The illustrations are good and reflect the plot.

The writing is easy to get into and the mystery a fun one. You will enjoy this. Fast paced and short, a good book. You do not need to read the other books first before you read this one.

Thank you, Common Deer Press, for the advance reading copy.

This is a great book for older children, as it combines some fun maths problems and maths learning alongside a really gripping mystery story. As a teacher, I can see how this book could be used to teach a class a wide variety of different topics as well as maths - there are great links to art, Egypt and music. I think this would be a really good book to study with a class.
There are four children who are friends, and who work together with the FBI to solve a mystery. As this is the fifth in the series, it does make me want to go back and read the first one, and perhaps some of the other ones too. There are several references throughout the book to things which have happened before. Most of these references are not important, and I would miss them out if I was reading the book to a class. However, it would have been handy to have more background information about how they knew Agent Carlson.
So although I would love to read this book to a class, it doesn't quite stand alone, and I would probably read them the first book before reading this one, or I would read the first one myself, and then tell them a few background details about the children and Agent Carlson before we read this one.

.Note: I received a digital review copy of this book from the publisher through NetGalley.

The Math Kids is like the TV show Numbers, but for kids. Like the show Numbers, the Math Kids shows how math can be used in various situations, including solving mysteries for the FBI!

This is a book that every elementary school (and perhaps even middle schools and high schools) should carry. I love that the aim of this series is to make math fun and interesting, and to highlight the various different applications that math has in the real world.

This is very much a book for kids (with an improbable mystery and involvement with the FBI) but even as an adult, I was surprised by how much I enjoyed reading this book. I loved learning about Pascal's triangle and had fun discovering all the various patterns that can be found within this great triangle.

In this episode I find the plot very interesting, and the educational math is very good, but there are a few strange things I don't like.

This book was most certainly captivating and entertaining, and just as mysterious and wonderful as the rest of the books in this series.
All maths lovers will most certainly love this!
I had so much fun reading it!!
Thank you publisher and netgalley for a copy!

.Thank you so much netgalley providing an arc!
I really like the worldbuilding, and how the author can create a world that has the capability of making us vicariously live through it. I feel like the introduction was a bit too slow-paced for me. The characters are fairly interesting.
Henceforth, it was quite a good read.