Challenging math problems worth solving.

The name “Open Middle” might sound like a strange name for a website about math problems. However, it references a very specific type of problem we try to encourage here. Most of the problems on this site have:
* a “closed beginning” meaning that they all start with the same initial problem.
* a “closed end” meaning that they all end with the same answer.
* an “open middle” meaning that there are multiple ways to approach and ultimately solve the problem.

Open middle problems generally require a higher Depth of Knowledge than most problems that assess procedural and conceptual understanding. They support the Common Core State Standards and provide students with opportunities for discussing their thinking.

Tag Line: Challenging math problems worth solving

A collection of math problems that require some good thinking, and maybe a few attempts. The idea is to move beyond procedural understanding.

The collections are sorted from grades Kinder to High School (for common core standards in the US - but probably transfer well). The problems usually involve some blank spots which must be filled with numbers. In many of the problems you can not use a digit more than once.

Like similar sites that provide these problem style questions, you can submit your own to add to the collection.