What is the trachtenberg method?

A method of adding columns of numbers and accurately checking the result without repeating the first operation. An intermediate sum, in the form of two rows of digits, is produced. The answer is obtained by taking the sum of the intermediate results with an L-shaped algorithm.

My children repeatedly failed arithmetic until I sent them to learn the trachtenberg method, were able to perform amazing calculations in seconds. The Trachtenberg system, if mastered, can get rid of the routine arithmetic that is part of everyone's daily work. I also read that Trachtenberg's system could have far-reaching implications for education and science.