What is the square root of 9?

So, as I was putting Bryce to bed tonight he asked me what the square root of nine was. What?! You are how old? Why do you even know that word? I told him three. I asked where he had learned about square roots. He told me that Monte had told him what the square root button meant on a calculator. So then I decided to ask Bryce some square root questions just to see if he understood without the calculator. I started small, 4. He answered 2. So then I asked 16. He answered 4. Okay, so now I really wanted to challenge his brain. I asked 81. Not kidding, in about 3 seconds he said 9. I asked one more, 100. He looked at me like I had just asked him to count to 5. 10 he replied. Okay I found one that took him a little bit to figure out, 144. When he said 12 I asked him how he did that one. He told me that 10 times 12 is 120 so then you just have to add 24 because you have two more 12's left and that makes 24. Sometimes I wish that I could see how his brain works. It amazes me how he can mentally do math so quick in his head. Keep it up Bryce!