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 of the current revolution in mathematics teaching known as the new math.

So as a public 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 "Ed biz." 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 is six, but if you're over 35 and went to public school you say eight from 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 can't three from two,
Two is than 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 three, that's nine.
Is clear?

Now instead of 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 in the hundreds place.

the three you then use one
To ten ones...
(and you know why four minus one
Plus ten is minus one?
addition is commutative, right.)
And so you thirteen 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 left two.
And you take away one 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 to review math.
so simple,
So simple,
only a child can do it!
Now 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 missing two fingers. shall we have a go at it? hang on.

You can't three from two,
Two is less three,
So you look at the in the eights place.
Now really four 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,
is ten base ten,
And you take away three, seven.

Now instead of four in the eights
got three,
'cause you one,
is to say, eight, to the two,
But you can't seven from three,
So you at the sixty-fours.

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

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

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

for new math,
New-hoo-hoo-math,
It do you a bit of good to review math.
so simple,
So simple,
only a child can do it!

Come tomorrow night. we're gonna do fractions.