Luyện nghe bài hát New Math

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 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 room I've worked for
a while that 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 - 173.

Now remember how we used to do that. three from two is nine; carry the one, and if you're under 35 or went to a private school you say seven from three is six, but if you're over 35 and went to public school you say eight four is six; carry the one so we have 169, 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 take three from two,
Two is less three,
So you look at the four in the place.
Now that's really tens,
So you it three tens,
Regroup, and you a ten to ten ones,
And you add to the two and get twelve,
And you take away three, nine.
Is that

Now of four in the tens place
got three,
'cause you one,
is to say, ten, to the two,
But you can't take seven three,
So you look in the place.

the three you then use one
To ten ones...
(and you know why four plus one
Plus ten is fourteen minus
addition is commutative, right.)
And so you have tens,
And you take seven,
And that five...

Well, six actually.
the is the important thing.

Now go to the hundreds place,
And you're with two.
And you take one from two,
And leaves...?

get one?
Not bad for the day!

for new math,
New-hoo-hoo-math,
It won't do you a bit of good to math.
so simple,
So simple,
That 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 ten really
if you're missing two fingers. shall we a go at it? hang on.

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

Now of four in the eights place
got three,
'cause you one,
is to say, eight, to the two,
But you take seven from three,
So you at the sixty-fours.

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

the three you then use one
To make ones,
And you add ones to the three,
And you get one-three eight,
Or, in words,
In base ten you eleven,
And you take seven,
And from eleven is four.
Now go to the sixty-fours,
And you're left two,
And you away one from two,
And leaves...?

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

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

Come back night. we're gonna do fractions.