What's the Name of That Book??? discussion

I read this book in the mid-90s and it could have been late 80s through mid-90s. Possibly part of a series, it was similar to Encyclopedia Brown in that it had young detectives solving mysteries for other kids in short stories. The difference is that the mysteries can be solved by the reader using logic grids and it in fact teaches how to create and solve them. The main characters are a boy and a girl -- the boy acts as the main detective and the girl is kind of like a "Dr. Watson" character.

A long shot - Logic Puzzles (Usborne SuperPuzzles) by Mark Fowler?

One copy on eBay shows some of the inside pages/ illustrations:
https://www.ebay.com/itm/274997514196

Is each mystery just a few pages long - or a story in a chapter?

Ha! I've been searching for years and after one last search after posting here: It's Super Sleuth, by Jackie Vivelo. The one I read was the 2nd: Beagle in Trouble