Lower eight type direct adding and subtracting abacus

Abstract

The invention discloses a direct-adding and direct-subtracting abacus with eight beads on the bottom deck. The traditional abacus has a plurality of arithmetic facts and is rather complex and difficult when in learning and understanding as well, and can not realize direct adding and direct subtracting, and the abacus is difficult to be combined with written calculations of the modern mathematics education and to represent the learning function. In order to solve the problems, the invention provides the direct-adding and direct-subtracting abacus with eight beads on the bottom deck improved based on the traditional abacus, and the abacus changes the five lower beads on the bottom deck of the traditional type abacus into eight lower beads, and becomes a type abacus, one of upper beads represents 5, one of lower beads represents 1, or is changed into a or type abacus. The abacus need no fact when in computation, and is easy for learning and understanding, any one can use the abacus as long as being able to count and jerk beads, and the abacus can realize the direct adding and direct subtracting, and can be combined with the written calculations of the modern mathematics education for enabling people to better understand the concepts of carrying and backing.

Description

technical field [0001] The invention relates to a teaching aid, in particular to an abacus. Background technique [0002] Abacus is a traditional Chinese calculation tool and an important invention in ancient China. The use of abacus and abacus is not only convenient for calculation, but also has the effect of exercising thinking ability. Using the abacus requires the close cooperation of the brain, eyes, and hands. Therefore, many schools and parents use the abacus to train children's thinking and calculation skills. Traditional abacus generally adopts the bead structure of "up two down five", "up two down four", "up down five" or "up down four". The calculation of this kind of abacus requires a separate set of formulas: [0003] Addition table [0004] Add one: one to one, one to five to four, one to nine to one; [0005] Add two: two to two, two to five to three, two to eight to one; [0006] Add three: three to three, three to five to two, three to seven to one; ...

AI Technical Summary

Problems solved by technology

[0023] There are so many formulas, and there are 2 to 3 situations for each addition or subtraction of a number, it is more complicated to learn and difficult to understand

This set of formulas is only applicable to the traditional abacus, and cannot be used in other places. It is easy to forget after a long time. It can only be used on the premise of memorizing the formulas. During the calculation, follow the formulas to dial the beads. The problem is that it is impossible to achieve direct addition and subtraction,

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