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​UNUMA KEISUUKAN aims to develop mathematical thinking, utilizing the Soroban and mental calculation skills.


The learners in elementary school will be working on Mathematics when advancing to junior high school, where they need a skill to make a full use of numbers and to create formulas based on a good understand on these quality, in addition to the calculation skill.

Mathematical skill
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Mathematical Combination

​<Textbook of advanced level>

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Mathematical Combination

In other words, to reach right answers to mathematical questions, the skill of accurate calculation would not be enough.  Another requirement is a skill to understand the idea and the logic of mathematical world, including the nature of numbers and formulas, and the intention of the questions,  


Mathematical combination is a textbook developed based on the concept above, by Mr. Sugawara, who manages and teaches at Sugawara Soroban School in Tokyo.  And many learners at UNUMA KEISUUKAN, from the time of elementary school ages, work on this textbook to understand mathematics, coping with difficult questions at a level of junior high school grades 2 or 3 mathematics. 

Mathematical thinking

It is not rare to find difficulty in and struggle with mathematics in the very beginning of the introduction once after entering junior high school, even for the one who used to gain high grades in the arithmetic test at the elementary school.  Mathematical combination takes an unique approach to mathematics from a view that mathematics is not the extended subject of arithmetic.

Training using Mathematical combination at UNUMA KEISUUKAN allows the learners to preparatory develop mathematical thinking from the elementary school years.  Many of those who had studied this textbook later on felt its effect, saying that they were able to smoothly start mathematics study at junior high school, without feeling difficulty, or they became good at mathematics.

Mathematical thinking as well as a high sense of numbers is a necessary skill in daily life, and also a powerful skill that can be applied in any fields, such as economics, management, finance, manufacturing, IT and healthcare, etc, which the learners would chose as their business field in the future after grown up.



We encourage all the learners at UNUMA KEISUUKAN to work well on Mathematical combination along with Soroban and mental calculation, to gain even a stronger skill of "numbers" in a broad sense.

Example of questions

Gradually advancing from basic to high level questions.

15+15....... and 21+21....... when the sum becomes equal?

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