**Dewey**:

*[singing]*Math is a wonderful thing. Math is a really cool thing. So get off your 'ath, let's do some math. Math, math, math, math, math. Three minus four is...

**Summer**: Negative one.

**Dewey**:

*[singing]*That's riiiiight. And six times a billion is...

**Marco**: Six billion?

**Dewey**:

*[singing]*Nailed it! And 54 is 45 more than...What is the answer Marta?

**Marta**: Nine.

**Dewey**:

*[singing]*No it's eight.

**Marta**:

*[singing]*No, it's nine.

**Dewey**:

*[singing]*Yes, I was just testing you, it's nine. And that's a magic number.

Dewey : [singing] Math is a wonderful thing. Math is a really cool thing. So get off your 'ath, let's do some math. Math, math, math, math, math. Three minus four is...
Summer : Negative one.
Dewey : [singing] That's riiiiight. And six times a billion is...
Marco : Six billion?
Dewey : [singing] Nailed it! And 54 is 45 more than...What is the answer Marta?
Marta : Nine.
Dewey : [singing] No it's eight.
Marta : [singing] No, it's nine.
Dewey : [singing] Yes, I was just testing you, it's nine. And that's a magic number.

http://www.moviequotedb.com/movies/school-of-rock/quote_42280.html