The Math Inspectors

An Amazon Best Selling series, perfect for middle-grade readers!

Join Stanley, Charlotte, Gertie, Felix, and Herman as they solve crimes using wit, humor, milkshakes... and even a little math.


What Are People Saying?

Juggling The Numbers

"Clever, humorous and well-written detective mystery targeted for late elementary and middle school readers. I must admit the plot kept me guessing and entertained. Chapters are short and easy to read. Pencil sketches are an added bonus. I particularly enjoyed the way that the authors found a way to integrate those dreaded hard to solve math word problems right into the story line."

Amazon Reviewer

For The 8 To Tween Set

"This is a fun math story for the 8 to Tween set, with well developed characters who could jump onto the Saturday morning TV screen and find a comfortable home on PBS. I look forward to more in this series for myself and the kids in my life!"

Amazon Reviewer

Math Is Useful At The Crime Scene

"Great book for late elementary and middle school youth.... detectives who use math to solve the crime. Also teaches that "word problems" are real life math. Cute story even teachers and parents will enjoy. Math can be FUN!"

Amazon Reviewer

Are You Ready To Be A Math Inspector?

If you've read any of the Math Inspectors books, you're probably hooked on crime solving, math problems, and chocolate milkshakes. Well, we can't help you with the milkshakes. But if you've answered the bonus problems at the end of the book, check your answers below and find out just how smart you really are.

  •    Book 1    
  •     Book 2   
  •     Book 3   
  •     Book 4   
  •     Book 5   
   Book 1    

Check Your Math!

Answers to the bonus questions at the end of BOOK 1:

Problem 1:

Polly can buy 9 brooms (and have some change left over)

Problem 2:

Stella spent $204.00 attending Rhyming Camp

Problem 3:

Felix would eat 70.5 truffles for $123.38 & get sick immediately

Problem 4:

Wervish would get 159 votes and Martridge would get 141 votes

    Book 2   

Check Your Math!

Answers to the bonus questions at the end of BOOK 2:

Problem 1:

Mr. Under sells 67 hotdogs per hour (answer is rounded)

Problem 2:

Felix needs 1.25 gallons of melted chocolate

Problem 3:

Felix needs 44 (1-pint jars) to sell all of that delicious soup

Problem 4:

Felix's shoulder will stop functioning in 349 minutes

    Book 3   

Check Your Math!

Answers to the bonus questions at the end of BOOK 3:

Problem 1:

It will be 49/100 on the Boring Scale

Problem 2:

Gertie will pay $10 plus $13 for a penalty (for a total of $23)

Problem 3:

Gertie caught %300 more

Problem 4:

92 hours of shoveling

Problem 5:

3/4 of a foot taller

    Book 4   

Check Your Math!

Answers to the bonus questions at the end of BOOK 4:

Problem 1:

We will make $4.19 per cat that we wash

Problem 2:

We would need to wash 478 cats

Problem 3:

Smoothie 1 = $.84, Smoothie 2 = $.68, Smoothie 3 = $.39 profit

Problem 4:

Would need to sell 513 smoothies

    Book 5   

Check Your Math!

Answers to the bonus questions at the end of BOOK 5:

Problem 1:

The next number will be 16

Problem 2:

Begin with 1, and skip count by 3

Problem 3:

A 1/9 chance, or 11.1%

Problem 4:

A 1/6 chance, or 16.7%

Problem 5:

Gertie would finish in 20 seconds, and Felix would finish in 24 seconds. So ger

Collect all 5 of the Amazon Best Selling

Math Inspectors Books & More!


The Case of the Claymore Diamond

The Claymore Diamond is missing! And the Math Inspectors think the wrong man has been arrested... but can they prove it?


The Case of the Mysterious Mr. Jekyll

When Ravensburg is hit by acts of hilarious vandalism, the Math Inspectors are called in...but is to solve the case or take the fall?  


The Case of the Christmas Caper

What's the worst possible Christmas crime? It's the one the Math Inspectors face in this story. Can they save Christmas?


The Case of the Hamilton Roller Coaster

When the Math Inspectors are targeted by a criminal mastermind, more than their favorite roller coaster is on the line. What's going to happen?


The Case of the Forgotten Mine

A field trip to an abandoned mining town...what could go wrong? How about everything! And this time, things could turn explosive.

Math Inspector Notebook

The Math Inspectors: Top Secret Journal

Are you ready to be a Math Inspector and solve cases of your own? Then you're going to need a journal to write down all your clues! 

Ready To Be An Author?

The Math Inspectors: Make Your Own Comic Book

This book has 120 PAGES OF BLANK COMIC STRIPS just waiting for your imagination!Write your own the math mystery for The Math Inspectors: Stanley, Charlotte, Gertie, Felix, and Herman. Or, make your own adventure!

Math Inspector Class Notebook

The Math Inspectors: Math Class Notebook

A Lined Journal For Math Class!

Hey Fellow Math Inspectors! If you want to get better at solving mysteries, you know what you need to do...keep getting better at math! One great place to get better at math is MATH CLASS, of course.  

Meet The Math Inspectors &

A Few Other Characters


Not only did Stanley come up with the bright idea of starting the Math Inspectors with his friends, but he's the heart of the group. If he knows there's a math mystery to be solved, he never gives matter what!


Charlotte has been Stanley's best friend ever since she can remember. Brave, loyal, athletic, and a real math lover, Charlotte is a key member of the crew. Luckily for the Math Inspectors, she also has a photographic memory! Not a bad skill for a detective.


Gertie may be the shortest member of the Math Inspectors, but she is has the biggest personality. Feisty but loyal, her math specialty is word problems, and she always has a notebook ready to jot down important notes and complicated problems.


Felix loves snacks and hates squirrels. He and Gertie are best pals, even though he drives her a bit crazy. Felix is always fun to have around, but don't let that fool you! He's the most advanced mathematician on the team.


Herman wasn't part of the team from the beginning. He wasn't even friends with the rest of the Math Inspectors. In fact, his unique talents aren't mathematical. But rest assured, Herman has become an indispensable part of the Math Inspectors.


Polly Partridge is DEFINITELY NOT a Math Inspector! She the leader of the English Club, and she's convinced that people who like math more than Shakespeare are crazy. She causes all sorts of problems for the Math Inspectors at school... and sometimes with the police as well.

Officer Evans

Officer Bobby Evans is a standout in the Ravensburg Police Department. Having spent years as a resource officer, Evans knows that Stanley and his friends are smart kids. When the kids turn into amateur detectives, they put a lot of trust in Evans to back them up.

Chief Abrams

Ravensburg Police Chief Abrams does not like amateur detectives messing in his business of crime solving. And he doesn't like kids very much, either. So you can imagine how much Chief Abrams loves working with the Math Inspectors! Answer: not very much.

Who Is MacBeth?

Stanley, Charlotte, Gertie, Felix, and Herman have solved lots of problems and stopped many criminals...maybe one too many! Now, one of those criminals wants a little payback. But who is MacBeth? The clues are there. Read closely and see if you can find out who this mastermind is, even before the Math Inspectors do!

Meet The Authors

If you liked The Math Inspectors, check out our other works!

Daniel Kenney

Dan is the husband of Teresa, father of many children, teacher of many students, and writer of many stories for people of all ages, including the wildly successful Remi Muldoon series, the Persistence Project books, and The History Mystery Kids.

Check out all of Dan's work here.

Emily Boever

Emily is the wife of Matt, a homeschooling mother of many children, and a teacher of typical and dyslexic students, both in person and online. Emily specializes in the topics of homeschooling, history, non-fiction research, storytelling, and dyslexia awareness.

Check out Emily's online classes here.