My DS7 started in piano @ 5years of age. He told me a few months into it that the keys left of middle C were negative numbers and the keys right of middle C were positive numbers. he then said the music sheet was the equation.

I asked him how do you solve the equation?

He told me by making your hands play the music correctly.

Here is his latest video on Youtube of his playing


DS9 - Starting 9th grade
DS7 - Starting 5th grade