WEBVTT

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So, this is my grandfather,

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Salman Schocken,

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who was born into a poor and uneducated family

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with six children to feed,

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and when he was 14 years old, he was forced to

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drop out of school in order to help put bread on the table.

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He never went back to school.

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Instead, he went on to build a glittering empire

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of department stores.

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Salman was the consummate perfectionist,

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and every one of his stores was a jewel

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of Bauhaus architecture.

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He was also the ultimate self-learner,

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and like everything else, he did it in grand style.

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He surrounded himself with an entourage

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of young, unknown scholars like Martin Buber

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and Shai Agnon and Franz Kafka,

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and he paid each one of them a monthly salary

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so that they could write in peace.

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And yet, in the late '30s, Salman saw what's coming.

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He fled Germany, together with his family,

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leaving everything else behind.

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His department stores confiscated,

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he spent the rest of his life in a relentless pursuit

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of art and culture.

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This high school dropout

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died at the age of 82,

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a formidable intellectual, cofounder and first CEO

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of the Hebrew University of Jerusalem,

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and founder of Schocken Books,

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an acclaimed imprint that was later acquired

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by Random House.

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Such is the power of self-study.

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And these are my parents.

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They too did not enjoy the privilege of college education.

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They were too busy building a family and a country.

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And yet, just like Salman, they were lifelong,

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tenacious self-learners, and our home was stacked

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with thousands of books, records and artwork.

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I remember quite vividly my father telling me

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that when everyone in the neighborhood will have a TV set,

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then we'll buy a normal F.M. radio. (Laughter)

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And that's me,

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I was going to say holding my first abacus,

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but actually holding what my father would consider

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an ample substitute to an iPad. (Laughter)

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So one thing that I took from home is this notion

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that educators don't necessarily have to teach.

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Instead, they can provide an environment and resources

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that tease out your natural ability to learn on your own.

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Self-study, self-exploration, self-empowerment:

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these are the virtues of a great education.

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So I'd like to share with you a story about a self-study,

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self-empowering computer science course

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that I built, together with my brilliant colleague Noam Nisan.

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As you can see from the pictures, both Noam and I

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had an early fascination with first principles,

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and over the years, as our knowledge of

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science and technology became more sophisticated,

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this early awe with the basics

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has only intensified.

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So it's not surprising that, about 12 years ago, when

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Noam and I were already computer science professors,

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we were equally frustrated by the same phenomenon.

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As computers became increasingly more complex,

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our students were losing the forest for the trees,

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and indeed, it is impossible to connect

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with the soul of the machine if you interact

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with a black box P.C. or a Mac which is shrouded

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by numerous layers of closed, proprietary software.

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So Noam and I had this insight that if we want our students

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to understand how computers work,

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and understand it in the marrow of their bones,

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then perhaps the best way to go about it

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is to have them build a complete, working,

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general-purpose, useful computer, hardware and software,

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from the ground up, from first principles.

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Now, we had to start somewhere, and so Noam and I

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decided to base our cathedral, so to speak,

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on the simplest possible building block,

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which is something called NAND.

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It is nothing more than a trivial logic gate

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with four input-output states.

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So we now start this journey by telling our students

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that God gave us NAND — (Laughter) —

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and told us to build a computer, and when we asked how,

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God said, "One step at a time."

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And then, following this advice, we start

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with this lowly, humble NAND gate,

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and we walk our students through an elaborate sequence

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of projects in which they gradually build a chip set,

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a hardware platform, an assembler, a virtual machine,

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a basic operating system and a compiler

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for a simple, Java-like language that we call "JACK."

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The students celebrate the end of this tour de force

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by using JACK to write all sorts of cool games

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like Pong, Snake and Tetris.

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You can imagine the tremendous joy of playing

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with a Tetris game that you wrote in JACK

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and then compiled into machine language in a compiler

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that you wrote also, and then seeing the result

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running on a machine that you built starting

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with nothing more than a few thousand NAND gates.

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It's a tremendous personal triumph of going

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from first principles all the way to a fantastically complex

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and useful system.

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Noam and I worked five years to facilitate

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this ascent and to create the tools and infrastructure

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that will enable students to build it in one semester.

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And this is the great team that helped us make it happen.

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The trick was to decompose the computer's construction

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into numerous stand-alone modules,

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each of which could be individually specified,

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built and unit-tested in isolation from the rest of the project.

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And from day one, Noam and I decided to put

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all these building blocks freely available in open source

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on the Web.

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So chip specifications, APIs, project descriptions,

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software tools, hardware simulators, CPU emulators,

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stacks of hundreds of slides, lectures --

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we laid out everything on the Web

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and invited the world to come over,

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take whatever they need,

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and do whatever they want with it.

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And then something fascinating happened.

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The world came.

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And in short order, thousands of people

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were building our machine.

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And NAND2Tetris became one of the first

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massive, open, online courses,

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although seven years ago we had no idea that what

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we were doing is called MOOCs.

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We just observed how self-organized courses

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were kind of spontaneously spawning

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out of our materials.

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For example, Pramode C.E.,

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an engineer from Kerala, India,

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has organized groups of self-learners

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who build our computer under his good guidance.

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And Parag Shah, another engineer, from Mumbai,

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has unbundled our projects into smaller,

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more manageable bites that he now serves

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in his pioneering do-it-yourself computer science program.

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The people who are attracted to these courses

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typically have a hacker mentality.

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They want to figure out how things work,

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and they want to do it in groups,

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like this hackers club in Washington, D.C.,

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that uses our materials to offer community courses.

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And because these materials are widely available

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and open-source, different people take them

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to very different and unpredictable directions.

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For example, Yu Fangmin, from Guangzhou,

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has used FPGA technology

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to build our computer and show others how to do the same

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using a video clip, and Ben Craddock developed

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a very nice computer game that unfolds

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inside our CPU architecture, which is quite a complex

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3D maze that Ben developed

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using the Minecraft 3D simulator engine.

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The Minecraft community went bananas over this project,

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and Ben became an instant media celebrity.

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And indeed, for quite a few people,

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taking this NAND2Tetris pilgrimage, if you will,

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has turned into a life-changing experience.

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For example, take Dan Rounds, who is a music

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and math major from East Lansing, Michigan.

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A few weeks ago, Dan posted a victorious post

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on our website, and I'd like to read it to you.

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So here's what Dan said.

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"I did the coursework because understanding computers

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is important to me, just like literacy and numeracy,

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and I made it through. I never worked harder on anything,

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never been challenged to this degree.

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But given what I now feel capable of doing,

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I would certainly do it again.

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To anyone considering NAND2Tetris,

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it's a tough journey, but you'll be profoundly changed."

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So Dan demonstrates the many self-learners

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who take this course off the Web, on their own traction,

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on their own initiative, and it's quite amazing because

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these people cannot care less about

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grades.

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They are doing it because of one motivation only.

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They have a tremendous passion to learn.

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And with that in mind,

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I'd like to say a few words about traditional college grading.

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I'm sick of it.

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We are obsessed with grades

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because we are obsessed with data,

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and yet grading takes away all the fun from failing,

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and a huge part of education

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is about failing.

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Courage, according to Churchill,

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is the ability to go from one defeat to another

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without losing enthusiasm. (Laughter)

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And [Joyce] said that mistakes

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are the portals of discovery.

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And yet we don't tolerate mistakes,

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and we worship grades.

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So we collect your B pluses and your A minuses

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and we aggregate them into a number like 3.4,

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which is stamped on your forehead

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and sums up who you are.

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Well, in my opinion, we went too far with this nonsense,

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and grading became degrading.

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So with that, I'd like to say a few words about upgrading,

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and share with you a glimpse from my current project,

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which is different from the previous one,

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but it shares exactly the same characteristics

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of self-learning, learning by doing,

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self-exploration and community-building,

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and this project deals with K-12 math education,

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beginning with early age math,

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and we do it on tablets because we believe that

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math, like anything else, should be taught hands on.

NOTE Paragraph

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So here's what we do. Basically, we developed

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numerous mobile apps, every one of them explaining

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a particular concept in math.

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So for example, let's take area.

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When you deal with a concept like area --

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well, we also provide a set of tools that the child

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is invited to experiment with in order to learn.

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So if area is what interests us, then one thing

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which is natural to do is to tile the area

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of this particular shape and simply count

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how many tiles it takes to cover it completely.

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And this little exercise here gives you a first

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good insight of the notion of area.

NOTE Paragraph

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Moving along, what about the area of this figure?

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Well, if you try to tile it, it doesn't work too well, does it.

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So instead, you can experiment

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with these different tools here by some process

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of guided trial and error,

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and at some point you will discover that one thing

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that you can do among several legitimate transformations

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is the following one. You can cut the figure,

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you can rearrange the parts, you can glue them

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and then proceed to tile just like we did before.

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(Applause)

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Now this particular transformation

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did not change the area of the original figure,

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so a six-year-old who plays with this

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has just discovered a clever algorithm

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to compute the area of any given parallelogram.

NOTE Paragraph

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We don't replace teachers, by the way.

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We believe that teachers should be empowered, not replaced.

NOTE Paragraph

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Moving along, what about the area of a triangle?

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So after some guided trial and error,

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the child will discover, with or without help,

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that he or she can duplicate the original figure

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and then take the result, transpose it,

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glue it to the original and then proceed [with] what we did before:

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cut, rearrange, paste — oops— paste and glue,

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and tile.

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Now this transformation has doubled the area

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of the original figure, and therefore we have just learned

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that the area of the triangle equals the area of this rectangle

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divided by two.

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But we discovered it by self-exploration.

NOTE Paragraph

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So, in addition to learning some useful geometry,

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the child has been exposed to some pretty sophisticated

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science strategies, like reduction,

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which is the art of

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transforming a complex problem into a simple one,

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or generalization, which is at the heart

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of any scientific discipline,

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or the fact that some properties are invariant

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under some transformations.

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And all this is something that a very young child

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can pick up using such mobile apps.

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So presently, we are doing the following:

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First of all, we are decomposing the K-12 math curriculum

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into numerous such apps.

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And because we cannot do it on our own,

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we've developed a very fancy authoring tool

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that any author, any parent or actually anyone

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who has an interest in math education,

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can use this authoring tool to develop similar apps

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on tablets without programming.

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And finally, we are putting together an adaptive ecosystem

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that will match different learners

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with different apps according to their evolving learning style.

NOTE Paragraph

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The driving force behind this project

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is my colleague Shmulik London,

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and, you see, just like

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Salman did about 90 years ago,

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the trick is to surround yourself with brilliant people,

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because at the end,

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it's all about people.

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And a few years ago, I was walking in Tel Aviv

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and I saw this graffiti on a wall,

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and I found it so compelling

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that by now I preach it to my students,

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and I'd like to try to preach it to you.

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Now, I don't know how many people here are familiar

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with the term "mensch."

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It basically means to be human

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and to do the right thing.

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And with that, what this graffiti says is,

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"High-tech schmigh-tech.

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The most important thing is to be a mensch." (Laughter)

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Thank you. (Applause)

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(Applause)