In mathematical calculation, the operation of multiplication starts from primary school and runs through the whole process of learning. When most students do multiplication, they will make mistakes if they are not careful about multiplication with more digits, so the more digits, the more annoying they are. Let's share the fast multiplication of three digits.

Multiply the single digits up and down; Cross product addition of single digits and ten digits (carry plus carry); Single digit and hundred digit cross multiplication plus ten digit up and down multiplication (carry plus carry); Ten-digit and hundred-digit cross product addition (carry plus carry); Multiply the hundredth bit up and down (carry plus carry)

For example, the pen calculation of 32 1 multiplied by 123\x0d32 1 multiplied by 123 is divided into four steps: the first step is to multiply 32 1 by the multiplier 3 on 123 to get 963; Step 2, multiply 32 1 by the multiplier 2 on the decimal place of 123 to obtain 642 decimal numbers, and the last digit of the number is aligned with the decimal place of the multiplier "2";

Step 3, multiply the number of bits of 123 by the multiplier 1 to get 32 1, and the last bit of the number is aligned with the number of bits of the multiplier "1"; Step four, add up the three times to get 39483. The multiplication of three digits is actually the same as the universal multiplication of two digits. Multiply any three digits and cross multiply the digits.

Then use the addition method to calculate, first multiply the single digits of two numbers, and the remaining single digits are the last digit of the result. If there is a decimal number, remember it in your mind first, then multiply it with the decimal digits of these two numbers, and their products add up again. In addition, in the first step, we calculate the decimal places to get a new two-digit number, and take one as the penultimate digit of the result.