Year 4 four rules mental maths A brand new category in Year 4, looking at a mixture of addition, subtraction, multiplication and division, all on the same page. Two of the sets are for mental arithmetic and two of the sets are for formal written methods of calculating. The latter are displayed in the correct format, but children will need to concentrate hard to carry out the correct calculation. Look out for more in this category in the future! Go to Year 4 Four Rules