Mr Dan Metcalf 
Codebusters [PDF ebook] 

Things are not going well for Jackson »Jax» Hibert. He wanted to fit in at his new school but now everyone knows he»s a maths whizz. Even worse, he»s been asked to join a secret (and totally uncool) group of code breakers: the Codebusters. Their mission is to solve mysteries and fight crime. So far, they»ve found a missing hamster…
But now, someone has stolen the school»s math prize from the trophy cabinet, and the only clue is a mysterious code. This looks like a case for the Codebusters!
Funny, exciting or a little bit spooky,
Black Cats are fast-paced stories with short chapters and illustrations throughout — stepping stones to reading confidence.
Book band: Dark Blue
Ideal for ages: 9+