I assume you mean three-digit number. The individual symbols used to write a number (0, 1, ... 9) are called digits.
Here is how you can solve this: The highest number you can write with three digits (that doesn't necessarily fulfil your conditions) is 999. Calculate its square root; round the result downwards to the nearest integer; square it again; add 1.
Then the number is called a "perfect square".Then the number is called a "perfect square".Then the number is called a "perfect square".Then the number is called a "perfect square".
For a number to be a perfect square, the number's square root has to be a whole number. 9 is a perfect square because its square root is a whole number, 3. If the square root of the number is a decimal, then it is not a perfect square. For example, 13 does not divide evenly so it not a perfect square.
If by 'perfect number' you mean 'perfect SQUARE', then yes. 49 is an odd number and a perfect square.
There is not a number that is a perfect square and perfect cube between 1 and 25.There is not a number that is a perfect square and perfect cube between 1 and 25.There is not a number that is a perfect square and perfect cube between 1 and 25.There is not a number that is a perfect square and perfect cube between 1 and 25.
There is no highest square number. If there was such a number then that number squared would be a higher square number!
20 is a not perfect square.
You take the square root of the number. If it is a perfect square, this will be a whole number. If it is not, it isn't a perfect square.
It is the definition of a perfect square.
Well, technically, it is the square of 11.18033989...but it is not a perfect square(a perfect square is the square of a whole number. 1,4,9,16,25,36,49,64,81,100,121,144,169,196,225,256, etc.)
It is a square number but not a perfect square number.
195 is a not perfect square.
No, 80 is a not perfect square.