1, two or three digits multiplied by one digit (no carry): starting from the single digit, multiply each digit of multiple digits by one digit in turn, then multiply it by the number of digits, and write the product under that digit.
2. When calculating the vertical two-digit number multiplied by a number in a column vertical way, a number must be multiplied by the number on each digit in the two-digit number in turn.
3. Two or three digits are multiplied by one digit (carry), and the column is calculated vertically. First, align one digit with multiple digits, and start counting from the unit. Which digit is multiplied by dozens will advance to the previous digit.
4. Multiply 0 with any number to get 0, and multiply 1 with any number except 0 to get this number.
In multiplication, multiplier is also called factor.
6. In the multiplication formula, the number after the equal sign is called the product.
7. There are two ways to check the complementary front of multiplication: one is to exchange the positions of two factors and multiply again to see if the results are the same; The other is to divide the product by one factor to see if the result is equal to another factor.
The origin of mathematics
Mathematics originated in ancient Babylon. Mathematics originated from the early production activities of human beings, and the ancient Babylonians had accumulated some mathematical knowledge, which could be applied to practical problems. As far as mathematics itself is concerned, their mathematical knowledge is only obtained through observation and experience, and there is no comprehensive conclusion and proof, but their contribution to mathematics should also be fully affirmed.
Mathematics is a universal means for human beings to strictly describe the abstract structure and mode of things, and can be applied to any problem in the real world. All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science. Different mathematicians and philosophers have a series of views on the exact scope and definition of mathematics.
Mathematics plays an irreplaceable role in the historical development and social life of human beings, and it is also an indispensable basic tool for studying and studying modern science and technology.