Read this Mathematical challenges Introduction to make full use of these resources. I wanted to improve the original resources as I wanted something more colourful and motivating for the students. I also moved the answers next to the questions to improve the flow of the lessons.
It is certainly easier to use. The children now solve a question and then they can immediately double check their answers with the rest of the class and discuss their different strategies for solving the problems.
I have used these teaching resources with my own class. The problems can be challenging for both the students and the teacher.