Numerical puzzles
All of these puzzles have a strong arithmetical element, and are thus ideal for making cross-curricular links with mathematics.
As much as finding the right answer, the focus should be on the comprehension skills needed to extract the essential information from each question. The language of mathematics, and particularly the way language is used to give form to essentially abstract concepts, can be a fertile area for discussion. Putting students in groups or pairs gives them a good chance to practise speaking to explain, justify and instruct.