1st Quarter - Blog #2 ... "All Squared Away!"

You have learned about 'squaring' a number at some point in your mathematical life (hint, hint)! So, look at the following numbers and determine which one is different from the others:
100, 300, 400, 900, 81, 25
Explain why the number that you chose is different from the others. Be sure to include at least FIVE sentences! Happy Blogging!!