Solution: Analysis: Because the root bond can't be used, it can't be solved by the square root method. Square root and square root are reciprocal calculations and can be solved by square root method.

Let y be the square of a,

Because 1002= 10? 000, so it can be determined that A is three digits.

Because 2002=40? 000, so y is between 100 and 200,

∵ 1702=28? 900, 1802=32? 400,

∴y should be a three-digit number greater than 170 and less than 180.

You can start with 17 1 and explore until you find it.

A is calculated as 178.

The value of y can be calculated as 3 1684.