Mental arithmetic (ANZAN) is a system where users mentally visualize an abacus to do calculations. Calculations can be made at great speed in this way. For example, in the Flash Anzan event at the All Japan Soroban Championship, champion Takeo Sasano was able to add fifteen three-digit numbers in just 1.7 seconds.

1. Concentration : soroban exam is only ten minutes and you could be calculating multiplications of a six-digit number by a five-digit number. In such condition, any mistakes blow your exam.
2. Inspiration : A doctor of Nippon Medical School has demonstrated that high ranked soroban users use their right brain while they calculate in mind by using soroban method. It´s said that the right brain manages inspiration such as problem solving and invention.
3. Memorization : “In the soroban method of mental calculation, th right brain memorizes the patterns of answers processed. In this method, answers are stored in the long-term memory as intuitive images.”
4. Insight : The process of calculation is so fast, you have to have the ability to observe attentively otherwise you make mistakes easily. Through soroban practice, your insight is hugely improved.
5. Information processing : When you do anzan (暗算/ mental calculation), you have to process numbers rapidly and accurately without any mistakes.
6. Speed reading and listening : In soroban practice, yomiagezan (読み上げ算) is introduced, which the problems are read out aloud while the students are expected to understand promptly and mentally process them. This is a good training of speed listening.

For more visit: Japanese abacus teacher wins Mental Calculation World Cup 

The League of Japan Abacus Associations, define six abilities cultivated by learning soroban…