Mental arithmetic, or “doing it in your head” is a skill that can take a long time to master. 


There are some tips and tricks that you can use, but most importantly you need a good understanding of the “times tables” to at least 12 x 12 to build on.



The section in yellow is the usual 12 x 12 that you would be expected to memorise, and the numbers in light blue are the “square” numbers. These are useful to memorise as they can help in other mental arithmetic problems later on.