Three digits should be aligned with two digits, and ten digits should be aligned with ten digits. First, multiply each bit of three digits with each bit of two digits, and the result is written on the digits. In this example, 243X2=486. Then multiply the ten digits of the two-digit number with each digit of the three-digit number respectively, and the multiplication result is written in the ten digits, for example, 243x3x3x10 = 7290.
When two results are added, the result is written backwards. Six digits are written directly, and ten digits add up to 17, which is written as 7. When the carry 1 is added with one hundred times of 4+2, it is written directly as thousands. That is 486+7290=7776. Note: Carry method, if the sum or multiplication number exceeds 10, carry it. For example, in the above example, 8+9 of the ten digits is 17, that is, 7 is written as 10 digits, and it will enter 1 one hundred times.
3X4 is 12, which also needs rounding. The carry number is usually written in lowercase between the previous line and the previous number, and will be added in the next step. If there is no carry, don't consider it. Multiplication is a shortcut to add up the same numbers. The result of its operation is called product, and "X" is the symbol of multiplication.
From the philosophical point of view, multiplication is the result of qualitative change caused by additive quantity. The multiplication of integers (including negative numbers), rational numbers (fractions) and real numbers is a systematic summary of this basic definition. Multiplication can also be seen as calculating the objects arranged in a rectangle (integer) or finding the area of a rectangle with a given side length.
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In the process of arithmetic development of various civilizations, the generation of multiplication operation is a very important step. A civilization can successfully develop counting methods and addition and subtraction operations, but it is not so easy to create simple and feasible multiplication methods.
The vertical calculation of multiplication seems simple, but it is necessary to master the formula table of 99 multiplication in advance; Considering this, this vertical calculation is not perfect. It will soon be seen that in the development of mathematics, different civilizations have created different multiplication methods, and some can even abandon the multiplication table completely.