The formula for calculating the square is to calculate the square of a number by multiplication. Specifically, the square of a number is equal to the product of this number and itself. For example, if the square of 4 is 4 times 4, the result is 16. Mathematically, this formula can be expressed as: a 2 = a× a, where a is a number. In addition to directly calculating the square by multiplication, there are other commonly used methods to calculate the square: look-up table method to make a square table, calculate the square value of commonly used numbers in advance and record it in the table, and get the square value by looking up the table. This method is suitable for small numbers, but not for large numbers. Formula method: how to use the square of a square to calculate? For any positive integer n, the square of n can be expressed as: n 2 = n× (n+1)×10+2. This formula is derived based on the carry representation of a number, and the square of a number can be calculated quickly through this formula.