5 worksheets, with each worksheet contains 5 questions that should be completed within 25 minutes. The worksheets mainly focus on problem solving skills. 

The questions aren't trivial, they have been chosen to be challenging. They aren't similar to the traditional questions that students are used to. 

The idea of the worksheets is to enhance the student's ability to reason about problems, and be able to use basic math skills to find a solution. 

The 25 problems target students at grades 5 - 6. You can try to use them with grade 4, but many of them will be over-challenging.