| 摘要 |
The invention relates to teaching aids for mental arithmetic in mathematics making it possible to organize teaching for children with the aid of game methods. The inventive figures for numbers A comprise two planks arranged to each other at an angle alpha (A) which is equal to an integral multiple of the right angle. The numbers ranging from 1 to 9 are arranged on the table (disk) called a telephone T-table having a 3x3 dimension and provided with a central cell (5). The turns of the T-table display all multiplication answers. The main direction for numbers 1, 2, 3, 4, 6, 7, 8, 9 corresponds to a vector coming from the center of the T-table. For odd numbers A=1, 3, 7, 9, the angle alpha (A) is read off from the direction towards 1, for even numbers A=2, 4, 6, 8 the angle alpha (A) is read off from the direction towards 6. The figures corresponding to numbers 5 and 0 are not attributed with the end value of the angles alpha (5) and alpha (0) or they are attributed with the infinite value.
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