My musical genius remains unappreciated

The scene: Firstborn is doing his math homework at the kitchen table. He's in third grade, so the worksheet is focused on subtracting three-digit numbers. So, for example:
 723
-382

...Except that, as with so much of current mathematical teaching, the idea isn't just to get the right answer. The assignment also wants him to estimate the answer first, by rounding the ones column and doing a much simpler approximation of the problem. So:
 72
-38

So, if your estimate comes out to 34, and your final answer is somewhere around 340, you probably did it right. I'd make fun of it, but this is actually a good trick to know. Anyway, Firstborn is working on these problems. I, of course, am helping him out...

...By singing.

Me: "Hey, I just met you,
and this is crazy,
but here's my numbers,
so estimate me!

Just round the ones place,
Let's don't get crazy,
so here's my numbers-
just estimate me!"

Firstborn: "Stop. Just stop."

Me: "Before I knew to estimate,
my math was so hard,
my math was so hard,
Before I knew to estimate my math was so, so hard."

Firstborn: "I will sing the Minecraft version at you. Stampy has a song about his dead dog."

Me: "I'll stop."

Victory to Firstborn. I like to think I was ahead on points, though.