(Tom Lehrer)

Some of you who have small children may have been put in the
embarrassing position of being unable to do your child's
arithmetic homework because of the current revolution in
mathematics teaching known as the new math. So as a public
service here tonight, I thought I would offer a brief lesson in
the new math. Tonight, we're going to cover subtraction.

This is the first room I've worked for a while that didn't have a
blackboard, so we will have to make do with more primitive visual
aids, as they say in the ``Ad Biz.''

Consider the following subtraction problem, which I will put up here.
Now, remember how we used to do that. 3 from 2 is 9, carry the 1
and, if you're under 35 or went to a private school, you say 7
from 3 is 6, but if you're over 35 and went to a public school
you say 8 from 4 is 6, carry the 1, so you have 169. But in the
new math:

From the three you then use one
To make ten tens
(And you know why four plus minus one
Plus ten is fourteen minus one?
'Cause addition is commutative, right!)
And so you've got thirteen tens,
And you take away seven,
And that leaves five.

Well, six actually. But the idea is the important thing!

Now go back to the hundreds place,
You're left with two,
And you take away one from two,
And that leaves?

Everybody get one? Not bad for the first day!


Hooray for new math,
New-hoo-hoo math,
It won't do you a bit of good to review math.
It's so simple,
So very simple,
That only a child can do it!

Now, actually, that is not the answer that I had in mind, because
the book that I got this problem out of wants you to do it in
base eight. But don't panic. Base eight is just like base ten
really -- if you're missing two fingers. Shall we have a go at
it? Hang on.

You can't take three from two,
Two is less than three,
So you look at the four in the eights place.
Now that's really four eights,
So you make it three eights,
Regroup, and you change an eight to eight ones,
And you add them to the two,
And you get one-two base eight,
Which is ten base ten,
And you take away three, that's seven.

Now instead of four in the eights place
You've got three.
'Cause you added one,
That is to say, eight, to the two,
But you can't take seven from three,
So you look at the sixty-fours.

Sixty-four? "How did sixty-four get into it?"
I hear you cry. Well, sixty-four is eight squared,
don't you see? (Well, you ask a silly question, and
you get a silly answer.)

From the three you then use one
To make eight eights,
And you add those eights to the three,
And you get one-three base eight,
Or, in other words,
In base ten you have eleven,
And you take away seven,
And seven from eleven is four.
Now go back to the sixty-fours,
You're left with two,
And you take away one from two,
And that leaves?

Now, let's not always see the same hands. One, that's right!
Whoever got one can stay after the show and clean the erasers.


Come back tomorrow night. We're going to do fractions.

Copyright Tom Lehrer
@school @kids @math
filename[ NEWMATH
PLEASE NOTE: Because of the volunteer nature of The Digital Tradition, it is difficult to ensure proper attribution and copyright information for every song included. Please assume that any song which lists a composer is copyrighted ©. You MUST aquire proper license before using these songs for ANY commercial purpose. If you have any additional information or corrections to the credit or copyright information included, please e-mail those additions or corrections to us (along with the song title as indexed) so that we can update the database as soon as possible. Thank You.