Trichome October 14, 2016 thcscience_admin The main article for this category is Mental calculation. Subcategories This category has only the following subcategory. Mental calculators (46 P) Pages in category "Mental calculation" The following 5 pages are in this category, out of 5 total. This list may not reflect recent changes. Mental calculationM Mental abacusR Rule of 72T Trachtenberg systemV Vedic Mathematics