| 摘要 |
The invention relates to instruments of the "ruler and abacus" type making it possible to immediately read a double-entry table, without a source of error (without following with the fingers). It comprises a fixed, square-shaped frame 1, a slide 2, into which is inserted the stud 3 of the ordinate cursors 5, their respective window 6 and 7, a module card 8 of the double-entry table type, a slot 9 allowing the module cards to be inserted. The problem is read through the windows 6 and 7 of the cursors 4 and 5. This result is read without searching nor handling other than that of writing in the windows of the cursors the data of the problem, at the intersection 4 and 5 of the cursors. Among the more beneficial applications of the invention may be mentioned, in the teaching field, means of learning, of memorising effortlessly, of making use accurately of Pythagorean tables, of understanding the principle n + 1, since the table appears as a whole, and since the reader is not a calculator, of reading, of learning colour synthesis. <IMAGE>
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