Hey, hey, Onee-chan, can you teach me addition?

I'm going to teach Hachi!

Addition? But I'm doing my homework right now...

All right, I'll teach you. Listen carefully. Let's say, for 1 + 1, that I have one piece of one kind of candy and one piece of another kind of candy. How many do I have all together? It's the same thing.

*woof woof*

Oh...

2 + 3 is similar...

*woof woof woof woof woof*

Hachi, be quiet for a little.

*woof woof woof woof woof woof woof woof woof woof woof woof woof woof woof*

You don't need to teach Hachi. He's much smarter than you already.

*toss*

Huh?

Hey, hey, Onee-chan, now that I understand addition, can you teach me subtraction next?

We'll do subtraction too, but first you should do multiplication. Multiplication uses addition, you see. Like, 2 × 3 means "add 2 to itself 3 times."

Hm... that's simple.

But when I get to 2 × 9 or 3 × 9 it gets hard...

That's why humans invented the civilized convenience of the pocket calculator. They wouldn't need it in the first place if they hadn't invented multiplication, but... humans are total fools.

Mm-hmm...

I remember all of my single-digit multiplication tables! 2 × 9 is 18, 3 × 9 is 27, and 9 × 9 is 81.

Mom, that's amazing!

So this is the insurmountable wall that exists between adults and children...