The root number 70 can't be opened, because the factor of 70 can't be converted into a square number, so it can only be estimated by a calculator, and it can only be roughly known that it is between 8 and 9, because 8 times 8.
Extended data
1, the meaning of the root sign
The root sign is a mathematical symbol used to represent the root operation of a number or an algebraic expression.
If a? =b, then A is the n-th root of B or A is the 1/n power of B, and the n-th handwritten and printed characters are represented by √ ~, and the number of roots or algebraic expressions are written in the area surrounded by the right side of the V-shaped part on the left side of the symbol and the lower part of a horizontal part above the symbol.
2. Arithmetic square root
Generally speaking, the number of radical signs is the arithmetic square root of this number.
For example, the root number 64 = the square of 8, and the square root of 64 should be: plus or minus 8; The arithmetic square root is: add 6.
If it is only the root number A: it means that you are required to find the arithmetic square root of this number, and it is only the positive root.
If you are seeking the square root, you are required to seek the square root of this number, that is, plus or minus two.