Try to extend the logic of this exercise across number bases other than 10. :) Cool video!

Unary-----------1 for every number. 1 11 111 1111 11111 Thats good for learning to count but not really anything else Binary----------1 for every power of 2 in other words 2 beads per row 1 10(this is 2 not 1) 11 100 101 Powers do go up fast but powers of 2 are the slowest Ternary---------1 for every power of 3 or 3 beads per row 1 2 10(3 not 2) 11 12 Quarternary---------1 for every power of 4 Twice as efficeint as binary to express the same thing Quinary----------1 for every power of 5 and we could go on to base 360 but 360 is a lot of beads. You know the babylonians used base 60. I find that really interesting. Time in hours:minutes:seconds is also base 60.

this did not help so much but would it just be easier to just use exponent to explain this topic?

Well, keep in mind that this is a 2nd grade math level concept. For example, if you were a second grader, wouldn't fractions be difficult to learn? I mean, if you have, I don't mean to bring you down or offend any exceedingly intelligent second grader. If your among them, or were, keep up the good work!

what is the ones place?

The ones place is the first number before a decimal. The numbers could be 1,2,3,4,5,6,7,8,9 or 0. In the number 235, the number 5 is in the ones place. In 14,567, 7 is the number in the ones place.

why do we use place value

to help represent numbers, using a base 10 system and to count easier and faster.

I’m ninety persent in second grade

Nice job Aman, I'm at 100%! Did you know that a percentage actually means a fraction? 96% means 96 divided by 100! So when they say "What is 40% of 100", you can solve it by doing 40/100 x 100. An easier way is to just do (40 x 100) divided by 100.

Shouldn't there be 9 beads in each row?

At 0:28 they say that there is ten beads in each row. They did it because it is easy to find multiples of 10 and the numbers are easy to deal with.

Main content

Arithmetic

Course: Arithmetic > Unit 5

Lesson 1: Intro to place value through 1,000

Intro to place value

Name: Intro to place value
Uploaded: 2014-02-21T00:00:56Z
Description: Sal introduces place value using a toy with beads (an abacus).

Google Classroom

Sal introduces place value using a toy with beads (an abacus). Created by Sal Khan.

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Jason Acacio
Posted 9 years ago. Direct link to Jason Acacio's post “Try to extend the logic o...”
Try to extend the logic of this exercise across number bases other than 10. :) Cool video!
Button navigates to signup pageComment on Jason Acacio's post “Try to extend the logic o...”
(190 votes)
Answer
- Anna
  Posted 9 years ago. Direct link to Anna's post “Unary-----------1 for eve...”
  Unary-----------1 for every number.
  1
  11
  111
  1111
  11111
  Thats good for learning to count but not really anything else
  Binary----------1 for every power of 2 in other words 2 beads per row
  1
  10(this is 2 not 1)
  11
  100
  101
  Powers do go up fast but powers of 2 are the slowest
  Ternary---------1 for every power of 3 or 3 beads per row
  1
  2
  10(3 not 2)
  11
  12
  Quarternary---------1 for every power of 4
  Twice as efficeint as binary to express the same thing
  Quinary----------1 for every power of 5
  and we could go on to base 360 but 360 is a lot of beads.
  You know the babylonians used base 60. I find that really interesting. Time in hours:minutes:seconds is also base 60.
  Comment on Anna's post “Unary-----------1 for eve...”
  (159 votes)
Eusebio Cortes
Posted 9 years ago. Direct link to Eusebio Cortes's post “how can one of those be ...”
how can one of those be 100
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(7 votes)
Answer
Zestfulmocha
Posted 9 years ago. Direct link to Zestfulmocha's post “Shouldn't there be 9 bead...”
Shouldn't there be 9 beads in each row?
Button navigates to signup pageComment on Zestfulmocha's post “Shouldn't there be 9 bead...”
(0 votes)
Answer
- RickGanesh
  Posted 9 years ago. Direct link to RickGanesh's post “At 0:28 they say that the...”
  At
  0:28
  they say that there is ten beads in each row.
  They did it because it is easy to find multiples of 10 and the numbers are easy to deal with.
  Comment on RickGanesh's post “At 0:28 they say that the...”
  (11 votes)
Jackie
Posted 6 years ago. Direct link to Jackie's post “this did not help so much...”
this did not help so much but would it just be easier to just use exponent to explain
this topic?
Button navigates to signup pageButton navigates to signup page
(9 votes)
Answer
- Spoopy_Monster
  Posted 5 years ago. Direct link to Spoopy_Monster's post “Well, keep in mind that t...”
  Well, keep in mind that this is a 2nd grade math level concept. For example, if you were a second grader, wouldn't fractions be difficult to learn? I mean, if you have, I don't mean to bring you down or offend any exceedingly intelligent second grader. If your among them, or were, keep up the good work!
  Comment on Spoopy_Monster's post “Well, keep in mind that t...”
  (7 votes)
meirastaylitt✨💍💦
Posted 8 years ago. Direct link to meirastaylitt✨💍💦's post “They told me what to do b...”
They told me what to do but i kind of stilldont get it
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(9 votes)
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Kai Brittain
Posted 6 years ago. Direct link to Kai Brittain's post “why do we use place value”
why do we use place value
Button navigates to signup pageComment on Kai Brittain's post “why do we use place value”
(5 votes)
Answer
- pfschnick
  Posted 6 years ago. Direct link to pfschnick's post “to help represent numbers...”
  to help represent numbers, using a base 10 system and to count easier and faster.
  Comment on pfschnick's post “to help represent numbers...”
  (7 votes)
janadarwish37
Posted 2 years ago. Direct link to janadarwish37's post “what is the ones place?”
what is the ones place?
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(6 votes)
Answer
- JoZie
  Posted 2 years ago. Direct link to JoZie's post “The ones place is the fir...”
  The ones place is the first number before a decimal. The numbers could be 1,2,3,4,5,6,7,8,9 or 0. In the number 235, the number 5 is in the ones place. In 14,567, 7 is the number in the ones place.
  Button navigates to signup page
  (4 votes)
Aman Flynn
Posted 3 years ago. Direct link to Aman Flynn's post “I’m ninety persent in sec...”
I’m ninety persent in second grade
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(4 votes)
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- xqcfan420
  Posted 3 years ago. Direct link to xqcfan420's post “Nice job Aman, I'm at 100...”
  Nice job Aman, I'm at 100%!
  Did you know that a percentage actually means a fraction?
  96% means 96 divided by 100!
  So when they say "What is 40% of 100", you can solve it by doing 40/100 x 100.
  An easier way is to just do (40 x 100) divided by 100.
  Comment on xqcfan420's post “Nice job Aman, I'm at 100...”
  (5 votes)
makamae_kaupu
Posted 7 years ago. Direct link to makamae_kaupu's post “Isn't this thing amazing ...”
Isn't this thing amazing or what?
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(6 votes)
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- bonnieatherton2015
  Posted 4 months ago. Direct link to bonnieatherton2015's post “no way this is bboorriinn...”
  no way this is bboorriinngg im 8!
  Comment on bonnieatherton2015's post “no way this is bboorriinn...”
  (1 vote)
david.1933796
Posted 3 years ago. Direct link to david.1933796's post “wow i never thought of th...”
wow i never thought of this!
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(6 votes)
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Video transcript

Voiceover:Hey Sal. Voiceover:Hello Brit. Voiceover:I picked this up at a garage sale and I know you like colors. Voiceover:I love colors. Voiceover:You wear colorful shirts everyday and I thought you might like this. Voiceover:I do, this is very kind, I like it. So what are you hoping to do with this thing? Voiceover:Well, at minimum just maybe represent numbers. Voiceover:To count, keep track of numbers? Voiceover:Counting the number of days or... Voiceover:One, two, three, yeah I can imagine doing that. Voiceover:Okay, so moving the beads down is a number, right? Voiceover:Yeah. Voiceover:There's 10. Voiceover:10 there, so maybe that would be 20, 30, 40, 50, 60, 70, 80, 90,100. Yeah, you could count 100 beads to keep track of things. Voiceover:What if I need to count 105 or 106? Do I need to buy another one? I don't even know where I would get more of these. Voiceover:That would be an option, maybe not an option if you don't know where to get it. Let's see, well the different colors, just like we have different forms of currency, maybe we can have each of these colors, maybe the columns, they represent a different amount. So this is 10 right over here, what if we had one of these red beads represent 10 of these blue beads in the first column. So then, you could go, this would be 10 or you could say that is 10. Voiceover:So there's two representations of 10 here? Voiceover:Yeah, they way we just worked it out here, yeah. And then 11 would be that. Voiceover:And this is 21. Voiceover: 21. Voiceover:Yep, you have two 10s and a one, 21. Voiceover:The wooden colored is going to represent all of the red beads. Voiceover:Yeah, that's a good system. If each column represents 10 of the beads to the column to it's right, that could be interesting. Because if this represents 10 red beads, that's 10 10s, this is equivalent to 100 blue beads. And so this would be equivalent to 10 of the brown beads, which would be 100 of the red beads, which would be 1000 of the blue beads, and this would be 10,000 of the blue beads and this would be 100,000 of the other blue beads, this would be 1,000,000 of the blue beads. Voiceover:So we're going to be able tor represent all the numbers in between one and say 1,000,000. Voiceover:I think we can. Voiceover:Let me just give you a number. What about 15,003? Voiceover:So let's think a little bit about this. So let's try with the big numbers first. So each of these is one, each of these is 10, each of these is 100, each of these is 1000. I don't have 15 of these, but these are 10,000. Each of these are 10,000. So this is one 10,000, then I could do five 1000s. One, two, three, four, five, so this is 15,000. So one 10,000, five 1000s, and zero 100s, zero 10s, and then throw a three there. So 15,003.