I have always been interested in learning Mental Calculation, but I think many beginners would agree with me when I say that I am unsure of where to look to learn techniques. There are a lot of books discussing different techniques such as Arthur Benjamin’s, the Trachtenberg System, and using an abacus. To aid with this problem and thus help spread the popularity of mental calculation, I wanted to ask seasoned mental calculators on the forum: What are the techniques you keep readily at hand to answer a question?
With your answers, we could compile a master list which would look like this
I think this would greatly help me and other beginners who would like to know what techniques are most helpful and what we should start learning if we’d like to excel at mental calculation.