So knowing place value makes adding subjects easier?

Nope it makes it million times harder than ever before!

Would the same idea work for hundreds?

Yes the same idea should work for hundreds. However if you where to work with monkeys you would have quite a few monkeys on your hand.

Who invented desmels? All so why do we even need desmels, what do they don't help use with anything.

decimals are used for exact numbers mainly used for dividing and look like this: (this is only an example and not the only way to use decimals) 10.0904 You will learn about decimals in 5th grade math

999+999=1000-1+1000-1=2000-2=1998

is zero the last number in the numbers?

There are an infinite amount of numbers! Even ones below 0. They are called negative numbers. Before 0 is negative 1, and before negative 1 is negative two. Here is a number line that might help. -5 -4 -3 -2 -1 0 1 2 3 4 5 |---|---|---|---|---|---|---|---|---|---|---|---| I started at -5, but there are many more numbers before that. Think of it in terms of cookies. Maybe there were 2 cookies. One for you and one for your friend. But, your friend took your cookie. So now, they owe you a cookie. This is the same as saying the have -1 cookies. They have two cookies, they owe you one. Now they have one cookie. That is the same as 2 plus -1. Or, just 2 minus 1. Crazy, right?

How do you count in binary, and what is 18 in binary?

I think _@Jerry Nilsson_ did a great job explaining how to write in binary, but he never went over what binary is, and why we do it the way we do it. The *binary* number system is a *base 2* number system. That means that each place value is *two times more than* the last place value. For example, we may have ones, tens and hundreds, and binary may have, ones, twos, fours, eights, and so on. Being a base 2 number system also means it consists of two characters, _or symbols._ These symbols are *ones and** zeros*. This means we add another place value every time one of the numbers becomes *greater than* the largest digit, which is *one*. _(In base ten, what we write in, the largest digit is *9*)_ So instead of counting like `0, 1, 2, 3, 4, 5, 6, etc.`, binary counts like this; `0, 1, 10, 11, 100, 101, 111, 1000, 1001, 1011, 1111, etc.` So instead of adding another digit after *9*, `(6, 7, 8, 9, *10*)`, we add another digit after the number *1*. `(0, 1, *10*)`. I hope this helped! Let me know if you still have any more questions about this!

Main content

Early math review

Course: Early math review > Unit 3

Lesson 1: Teens

Teen numbers: monkeys

Name: Teen numbers: monkeys
Uploaded: 2014-03-24T19:52:21Z
Description: Sal breaks the number 18 into 10 and 8.

Google Classroom

Sal breaks the number 18 into 10 and 8. Created by Sal Khan.

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alpharock24
Posted 3 years ago. Direct link to alpharock24's post “what is 567490005 + 23300...”
what is 567490005 + 2330009987=
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- Eddie
  Posted 3 years ago. Direct link to Eddie's post “It Is 2897499992”
  It Is 2897499992
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EzekielTweneboah
Posted 8 years ago. Direct link to EzekielTweneboah's post “So knowing place value ma...”
So knowing place value makes adding subjects easier?
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- Ahmed
  Posted 8 years ago. Direct link to Ahmed's post “Nope it makes it million ...”
  Nope it makes it million times harder than ever before!
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27hutre01
Posted 4 years ago. Direct link to 27hutre01's post “you need 8 monkeys to mak...”
you need 8 monkeys to make 18
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- apredator504
  Posted 4 years ago. Direct link to apredator504's post “You are on the right trac...”
  You are on the right track. You need 8 monkeys and an additional 10 monkeys to make 18 monkeys. 8+10=18
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carb0nshel1
Posted 6 years ago. Direct link to carb0nshel1's post “How do you count in binar...”
How do you count in binary, and what is 18 in binary?
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- Kaden Campbell
  Posted 6 years ago. Direct link to Kaden Campbell's post “I think _@Jerry Nilsson_ ...”
  I think @Jerry Nilsson did a great job explaining how to write in binary, but he never went over what binary is, and why we do it the way we do it.
  
  The binary number system is a base 2 number system. That means that each place value is two times more than the last place value. For example, we may have ones, tens and hundreds, and binary may have, ones, twos, fours, eights, and so on.
  Being a base 2 number system also means it consists of two characters, or symbols. These symbols are ones and* zeros*. This means we add another place value every time one of the numbers becomes greater than the largest digit, which is one. (In base ten, what we write in, the largest digit is 9)
  So instead of counting like 0, 1, 2, 3, 4, 5, 6, etc., binary counts like this; 0, 1, 10, 11, 100, 101, 111, 1000, 1001, 1011, 1111, etc. So instead of adding another digit after 9, (6, 7, 8, 9, 10), we add another digit after the number 1. (0, 1, 10).
  
  I hope this helped! Let me know if you still have any more questions about this!
  Comment on Kaden Campbell's post “I think _@Jerry Nilsson_ ...”
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Maryam A.K.
Posted 7 years ago. Direct link to Maryam A.K.'s post “Would the same idea work ...”
Would the same idea work for hundreds?
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- Blueberry Erath
  Posted 7 years ago. Direct link to Blueberry Erath's post “Yes the same idea should ...”
  Yes the same idea should work for hundreds. However if you where to work with monkeys you would have quite a few monkeys on your hand.
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  (2 votes)
kenzleekinnebrew
Posted a year ago. Direct link to kenzleekinnebrew's post “10+8=18 and 1234567891011...”
10+8=18 and 1234567891011121314151618
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GAVIN SPIDER-MAN
Posted 22 days ago. Direct link to GAVIN SPIDER-MAN's post “Who invented desmels? All...”
Who invented desmels? All so why do we even need desmels, what do they don't help use with anything.
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(2 votes)
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- Green Light
  Posted 20 days ago. Direct link to Green Light's post “decimals are used for exa...”
  decimals are used for exact numbers mainly used for dividing and look like this: (this is only an example and not the only way to use decimals) 10.0904
  You will learn about decimals in 5th grade math
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  (2 votes)
verasofiakafie
Posted 2 years ago. Direct link to verasofiakafie's post “Los 1 de los numeros son ...”
Los 1 de los numeros son los tens
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elizabeth.morris
Posted 21 days ago. Direct link to elizabeth.morris's post “what is 999 + 999”
what is 999 + 999
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- genna wells
  Posted 8 days ago. Direct link to genna wells's post “999+999=1000-1+1000-1=200...”
  999+999=1000-1+1000-1=2000-2=1998
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Kennedy Henyon
Posted 6 years ago. Direct link to Kennedy Henyon's post “is zero the last number i...”
is zero the last number in the numbers?
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- Dragonfly533
  Posted 6 years ago. Direct link to Dragonfly533's post “There are an infinite amo...”
  There are an infinite amount of numbers! Even ones below 0. They are called negative numbers. Before 0 is negative 1, and before negative 1 is negative two. Here is a number line that might help.
  -5 -4 -3 -2 -1 0 1 2 3 4 5
  |---|---|---|---|---|---|---|---|---|---|---|---|
  I started at -5, but there are many more numbers before that. Think of it in terms of cookies. Maybe there were 2 cookies. One for you and one for your friend. But, your friend took your cookie. So now, they owe you a cookie. This is the same as saying the have -1 cookies. They have two cookies, they owe you one. Now they have one cookie. That is the same as 2 plus -1. Or, just 2 minus 1. Crazy, right?
  Button navigates to signup page
  (2 votes)

Video transcript

Voiceover:Let's say that you're throwing a party, and as we all know, any party needs a sufficient number of monkeys. Right now you have 10 monkeys. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. But you would like to have 18 monkeys. How many more monkeys do you need in order to have 18 monkeys? I encourage you to pause the video and think about it on your own before I work through it. Remember, the goal here is to get to ... The goal here ... Let me write it this way. The goal here is to get to 18, 18 monkeys. Now what do we know about the number 18? Well the number 18, you have this 1 right over here in the tens place. That literally represents 1, 10. And then this 8 represents 8, 1's. Plus 8, 1's. That's the same thing as saying 1, 10 ... 1, 10, that's just a 10 right over there. And 8, 1's, that's just 8. 18 is the same thing as 10 plus 8. If we start with 10 monkeys, which is how many we have started with, how many more do we need to get to 18? Well, if you start at 10, you need 8 more to get to 18. We can verify that visually, if we like. Let's see. Let me copy and paste 1 of these monkeys. Copy. This is 10. Now, let's get to 18. 11, 12, 12, 13, 14, 15, 16, 17, and 18. And 18. How many more did we add? Well, once again, we started, we started with this 10 right over here. Let me box them off. We started with these 10 monkeys. That's 1 group of 10 right over there. We started with the 10. And then we added 8 more monkeys. 1, 2, 3, 4, 5, 6, 7, 8. 1, 2, 3, 4, 5, 6, 7, 8. So we started with 10. We added 8 more monkeys. We added 8 more monkeys to get, to get to 18. And once again, how did we first think about that? Well, 18 is 1, 10 plus 8, 1's. Or 10 plus 8.