Lattice algorithm, also known as carpet weaving, is a mathematical algorithm discovered in Italy more than 500 years ago. Later, it was introduced to China at the same time as the pen calculation in the Ming Dynasty. This algorithm needs to be worked out one by one by calculation, and then added. For example, let's say 46×75. What we do is divide it into four formulas: 40×5, 6×5, 40×70 and 6×70 to get 200, 30, 2800 and 420, and then add all the numbers to get 3450.
So many formulas are worked out one by one, and then added together, which is slow and easy to write, so everyone thinks the calculation is really annoying. There is a simplified method. The first factor on the square is 46, and the second factor on the right is 75.
Past lives of lattice multiplication
Lattice multiplication is a calculation method of multiplying two numbers, which was put forward by Italian mathematician pacioli in his book "Summary of Arithmetic, Geometry and Proportional Properties" in the middle of15th century. Lattice algorithm is between drawing lines and calculating formulas. According to legend, this method was first recorded in the book Lirowati written by Indian mathematician Bashgaro in 1 150. /kloc-was widely spread in Arabia after the 0/2nd century, then spread to Europe through Arabs, and soon became popular in Europe.
This method was later introduced to China, and Cheng Dawei, a mathematician in China in the Ming Dynasty, called it patchwork in his book Arithmetic Unity. These two methods are similar, but the line drawing algorithm is more intuitive and simple, and the lattice algorithm is between line drawing and formula. The grid is determined by the number of bits of each factor. If you multiply the number of digits m by the number of digits n, you will draw a grid of m × n. For example, if you multiply three digits by two digits, you will draw a 3×2 grid.
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