A perfect square is a number that can be expressed as the product of two equal integers.
The only way to accurately calculate if a number is a perfect square is to find the factors. Before we go through the trouble of finding the factors, there is a quick trick you can use to help determine if you need even need to do the extra work.
Try these steps first:
Let's try it...
Step 1:
What is the last number of 13,129,791? It is this number: 13129791. The answer is 1. Is 1 in the list of numbers that are never perfect squares (2, 3, 7 or 8)?
Answer: NO, 1 is not in the list of numbers that are never perfect squares. Let's continue to the next step.
Step 2:
We now need to obtain the digital root of the number. Here's how you do it:
If the answer is more than one digit, you would add each digit of the answer together again:
What is the digital root of number 13,129,791?
Answer: 6
Step 3:
So now we know the digital root of 13,129,791 is 6. Is 6 in the list of digital roots that are always a square root (1, 4, 7 or 9)?
Answer: NO, 6 is not in the list of digital roots that are always perfect squares. We can conclude that 13,129,791 IS NOT a perfect square and we don't need to factor!
Number | 13,129,789 | 13,129,790 | 13,129,792 | 13,129,793 |
Perfect Square? | no | no | no | no |