The root sign method is only applicable to the square root of any integer or finite decimal. Because there is no complicated formula on the Internet, we can only write it out as much as possible, and then explain it orally: suppose an integer is 1456456, and the root number should start from the unit, and every two digits should be marked, which is represented by' here. Then it becomes 1'45'64'56 after the tag. Then add 0 to the decimal point according to the number of decimal places to be opened. If the example here is an open integer, two zeros will be added. The reason will be clear when you understand this practice. ) The solution is as follows: several problems that need to be explained in the solution: 1, the ... is meaningless in the formula because it is online. It's all for typesetting. 3. Except "has special significance and helps to solve problems" in 1'45'64'56, the rest are added for typesetting, aligning positions and explaining the source of numbers. The cancellation of ...........1... 2 ... 0.8-...1...1'45' 64' 56.00 ... (1) ............./kloc. ............-.......22..| .45.................(2) ..............44 ..............-........240.|. 1'64..............(3) ....................0 ...............-.......2406.|. 1'64'56...........(4) .................. 1'44'36 .................-........24 / Kloc-0/28. | .20' 20' 00 ... (5) .................... 1 9' 29' 74 ..................-.......................10' 26, where step (1) means before the first' from the left. It is 1 in this problem that is used to make the square root, and the number is written on it. Step (2) is to write down the number between the second' number' and the first' number', that is, 45, as the dividend, multiply the number 1 written in the previous step by 20 as part of the divisor, and the other part will be judged to get a number A. This step judges that A should be 2, so the divisor is 22, and 2 is written as/kloc-. Step (3), the remainder 1 calculated in the previous division is removed, and the number 64 between the third number and the second number is also removed to form the number 164 as the divisor. Multiply the number written above 12 by 20 and add a number that can be used as the quotient of this step to form the divisor. Because this step determines that only 0 meets the conditions, the divisor is 240, the quotient is written on 0, and 164 is moved down to the remainder. Step (4), if you can understand it before, this step is actually just a repetition of the previous step. Remove 164 and 56 to get the dividend 16456, then multiply 120 by 20 and add 6 to get the divisor. At the same time, 6 itself is the quotient, and the remainder 2020 is obtained. Step (5) is still repeated. In particular, for numbers after the decimal point, 0' s complement number is enough, and it is still two digits plus one. To sum up, divide the first quantile first and then square the first quantile. If there is a remainder, it will move down and the second quantile will form a dividend. The divisor consists of the quotient obtained before multiplied by 20 and a certain number. This number will appear in the form of quotient in this step, so you need mental arithmetic or oral arithmetic to determine which number this number is from 0 to 9, and then move the remainder down until you get the answer. It is also necessary to explain.