Mary solved the problem, 57×135 in the movie 'Gifted'.
She did mental calculation which is called Trachtenberg system.
This video explains in detail how Mary solved the problem.
You can understand the process of Trachtenberg multiplication
#Gifted #calculation #Trachtenberg


a scene from the movie Gifted
what is the Mary's secret?
the process of solving 57×135 with Trachtenberg system.
introduction to Trachtenberg and Trachtenberg system