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SARAH HANSEN: Well, you have a
lot of followers of your 18.06

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videos.

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GILBERT STRANG:
That's wonderful.

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SARAH HANSEN: And I'll
read this quote to you.

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"A commenter even noted
that this is not lecture,

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this is art."

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GILBERT STRANG: Gosh.

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OK.

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Well, if you're going to ask
what's my system, I have none.

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I guess-- well, first
I like students.

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And I want to help.

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And maybe the key point
is to think with them.

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Not to just say, OK, here
it is, listen, listen up.

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I think through the question
all over again as they do.

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And you have to give time.

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You can't zip through a proof.

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Because this class has to be
sort of thinking with you.

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And that's-- yeah,
that's my thought.

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I don't know if I achieve it,
but I think it's the goal.

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SARAH HANSEN: One
of our users on OCW

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noted that during
lectures you sometimes ask

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rhetorical questions, or maybe
feign confusion as a way--

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GILBERT STRANG: Feign confusion?

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I'm confused.

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SARAH HANSEN: Are you?

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OK.

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GILBERT STRANG: Well, no.

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Well, no, it's probably true.

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That's maybe part of
not rushing through it.

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But getting-- so I'll pause
at the critical point, maybe.

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You have to give time to see,
OK, what's the next step?

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You know, mathematics
is beautifully ordered,

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and sensible, and logical.

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And linear algebra
is not too difficult.

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But still, you can't rush.

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You have to sort of see
the idea a few times.

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First maybe on the
board as symbols.

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But not everybody
picks up on symbols.

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Then you say, what does it mean?

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And then finally you
say, why is it true?

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But you don't say,
"Why is it true?

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Give the proof,"
the very first step.

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You want to make people
think, yeah, it is true.

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SARAH HANSEN: Others have noted
that you do this thing where

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you display your own
thinking kind of on the spot

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as you work through problems.

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GILBERT STRANG: Yeah.

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SARAH HANSEN: Is there ever
a risk in that for you?

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GILBERT STRANG: Oh, yes.

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And it happens, that
I lose the thread

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or I come up to a dead
end where I don't know

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what I'm supposed to do next.

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But generally, especially in
18.06, The basic linear algebra

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course that many
people have watched,

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there I kind of get it OK.

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Yeah, I've taught
it enough times

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to have a good chance
of getting it right.

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SARAH HANSEN: Is this a strategy
that you developed over time?

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You know, lots of people
are nervous to do that,

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to make themselves vulnerable
in front of a large lecture

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class like that.

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But you're working
problems in real time

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and demonstrating what happens
when you hit a dead end.

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GILBERT STRANG: Well,
that's OK, because students

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are going to hit dead ends, so
it seems to me it's OK for me

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to get stuck, too.

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And then if they see,
oh, OK, maybe this

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is the way to get
out of that corner.

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Yeah.

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So essentially I think the
thing is I like students.

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I like math.

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And putting them together is
just the best job in the world.

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SARAH HANSEN: Let's talk
about humor for a second.

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GILBERT STRANG: OK.

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SARAH HANSEN: You
have been known

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to say things like, keep things
in their Gauss-given order.

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GILBERT STRANG: I see.

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SARAH HANSEN: And other really
funny things that people

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just love.

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So what's the role of
humor in your teaching?

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GILBERT STRANG:
Well, maybe it's--

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which is what I'm saying
here, maybe the key point

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is to make it human.

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You know, you're a person,
like the student is a person.

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The book isn't quite a person,
but it was written by a person.

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And to see that it's just
like a natural thing to do.

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Yeah.

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Yeah.

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Yeah.

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SARAH HANSEN: So
one of our users

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was thinking about how you
teach complex material, how

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you convey it in ways that
are comfortable for students.

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And the user was
wondering, how do

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you know when to go into
detail and when not to?

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GILBERT STRANG: I suppose I try
to think it through once again.

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And then you sort
of automatically

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see the word-- you recognize
what words you need to use,

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and what the steps are.

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Yeah.

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If you're not
thinking it yourself,

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then you're probably
going too fast

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and not connecting with
the thinking of the class.

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SARAH HANSEN: And
how do you connect

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with the thinking of the class
when it's such a large lecture

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hall?

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And everyone's at a different
point in their understanding.

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GILBERT STRANG:
That's probably true.

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And of course, you don't
know what everybody

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is thinking in that class.

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But overall, if you get--

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if you stay sort of conscious
of the class, conscious of where

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they are, that's, I think,
the thing for any speaker,

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is to be conscious
of the audience

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and not just a A-B inverse.

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SARAH HANSEN: What
else would you

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like to add about teaching
18.06 linear algebra?

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GILBERT STRANG: Well, with
18.06 of course, I'm just--

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so, recently, Open
CourseWare, which I think

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was just such a great idea.

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Great idea for MIT.

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Great idea for faculty.

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So they did a count of the
number of viewers in 18.06,

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and it was 10 million.

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Which was like, woo.

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I never expected.

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But I do get nice,
really nice messages

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from all over the world.

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And I reply to
them far as I can.

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Sometimes they'll ask what's
a good way to learn math?

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I don't know if I have
an answer to that.

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But anyway, I try
to be encouraging.

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So yeah.

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It's been wonderful.

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Just having the video
lectures available

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allows everybody
to be in the class.

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Yeah.

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So, thank you all for
joining the class.

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Thank you.