Multiply any large number by 12 mentally in seconds To multiply any number by 12 just double last digit and thereafter double each digit and add it to its neighbour …
Multiply any large number by 12 mentally in seconds To multiply any number by 12 just double last digit and thereafter double each digit and add it to its neighbour …
Formulas of Number Series 1 + 2 + 3 + 4 + 5 + … + n = n(n + 1)/2 (12 + 22 + 32 + ….. + n2) …
