New Math

New Math
Composer(s): Tom Lehrer
Performer(s): Tom Lehrer



Some of you who have small children
may have perhaps 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 gonna 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 ed biz
Consider the following subtraction problem
which I will put up here: 342 minus 173
Now, remember how we used to do that:
But in the new approach, as you know
the important thing is to understand what you're doing
rather than to get the right answer
Here's how they do it now:

You can't take three from two
Two is less than three
So you look at the four in the tens place
Now that's really four tens
So you make it three tens
Regroup, and you change a ten to ten ones
And you add 'em to the two and get twelve
And you take away three, that's nine
Is that clear?

Now instead of four in the tens place
You've got three
'Cause you added one
That is to say, ten, to the two
But you can't take seven from three
So you look in the hundreds place

From the three you then use one
To make ten ones...
(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, that actually 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 'em to the two
And you get one-two base eight
Which is ten base ten
And you take away three, that's seven
Ok?

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, ya ask a silly question, ya get a silly answer...!

From the three, you then use one
To make eight ones
You add those ones 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

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!

Come back tomorrow night...we're gonna do fractions!