So slightly off-topic... I quit marijuana recently, and as I do these exercises and get further into Khan Academy, I keep wondering if people can do these exercises easily in their head. Give me a pen and paper and these problems are like nothing, because I understand them conceptually, but in my head I can barely keep track of the answers generated at each step. Just curious if I'm the only one that needs a pen and paper for this simple stuff.

Some people can do these kinds of things in their heads, but don’t beat yourself up if you can’t. It gets easier with practice and as you find your own shortcuts. :)

I now how to do it but I can't do it sideways I now it doesn't mater if it is sideways or not

Do it the way that makes it easier for you...but sometime in your life you will have to learn it sideways

so when you line up all the numbers will you subtract left to right or the other way around??

Like any regular subtraction problem, you will subtract right to left.

if I go on youtube and search this will this vid come up? Or is it only on the site?

did you know that this is on the site and on youtube too

What is "standard algorithm"?

It is the standard or original way to do the math, like dividing or multiplying.

Main content

5th grade (Eureka Math/EngageNY)

Course: 5th grade (Eureka Math/EngageNY) > Unit 1

Lesson 4: Topic D: Adding and subtracting decimals

Subtracting decimals: 9.57-8.09

Name: Subtracting decimals: 9.57-8.09
Uploaded: 2013-12-27T22:16:42Z
Description: To find the least common denominator of two fractions, we can either list out the multiples of the two denominators until we find a common one, or use prime factorization. Once we've found the least common denominator, we can rewrite the fractions so they both have this denominator, and then add them together.

CCSS.Math:

5.NBT.B.7

Google Classroom

To find the least common denominator of two fractions, we can either list out the multiples of the two denominators until we find a common one, or use prime factorization. Once we've found the least common denominator, we can rewrite the fractions so they both have this denominator, and then add them together. Created by Sal Khan.

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eye_travis
Posted a year ago. Direct link to eye_travis's post “So slightly off-topic... ...”
So slightly off-topic...

I quit marijuana recently, and as I do these exercises and get further into Khan Academy, I keep wondering if people can do these exercises easily in their head. Give me a pen and paper and these problems are like nothing, because I understand them conceptually, but in my head I can barely keep track of the answers generated at each step.

Just curious if I'm the only one that needs a pen and paper for this simple stuff.
Button navigates to signup pageComment on eye_travis's post “So slightly off-topic... ...”
(6 votes)
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- Johanna
  Posted a year ago. Direct link to Johanna's post “Some people can do these ...”
  Some people can do these kinds of things in their heads, but don’t beat yourself up if you can’t. It gets easier with practice and as you find your own shortcuts. :)
  Comment on Johanna's post “Some people can do these ...”
  (7 votes)
ProJorden💎🦄💎🐢🐢🐢🐢🐢🐢
Posted 9 years ago. Direct link to ProJorden💎🦄💎🐢🐢🐢🐢🐢🐢's post “I now how to do it but I ...”
I now how to do it but I can't do it sideways I now it doesn't mater if it is sideways or not
Button navigates to signup pageComment on ProJorden💎🦄💎🐢🐢🐢🐢🐢🐢's post “I now how to do it but I ...”
(3 votes)
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- Toby Harris
  Posted 3 years ago. Direct link to Toby Harris's post “Do it the way that makes ...”
  Do it the way that makes it easier for you...but sometime in your life you will have to learn it sideways
  Button navigates to signup page
  (4 votes)
EFHaas05😂
Posted 8 years ago. Direct link to EFHaas05😂's post “so when you line up all t...”
so when you line up all the numbers will you subtract left to right or the other way around??
Button navigates to signup pageButton navigates to signup page
(3 votes)
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- Johnson
  Posted 8 years ago. Direct link to Johnson's post “Like any regular subtract...”
  Like any regular subtraction problem, you will subtract right to left.
  Comment on Johnson's post “Like any regular subtract...”
  (4 votes)
FieldsJaden
Posted 9 years ago. Direct link to FieldsJaden's post “if I go on youtube and se...”
if I go on youtube and search this will this vid come up? Or is it only on the site?
Button navigates to signup pageComment on FieldsJaden's post “if I go on youtube and se...”
(2 votes)
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- EzekielTweneboah
  Posted 9 years ago. Direct link to EzekielTweneboah's post “did you know that this i...”
  did you know that this is on the site and on youtube too
  Comment on EzekielTweneboah's post “did you know that this i...”
  (3 votes)
@khanacademyuser
Posted 3 years ago. Direct link to @khanacademyuser's post “What is "standard algorit...”
What is "standard algorithm"?
Button navigates to signup pageComment on @khanacademyuser's post “What is "standard algorit...”
(2 votes)
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- Aditi
  Posted 2 years ago. Direct link to Aditi's post “It is the standard or ori...”
  It is the standard or original way to do the math, like dividing or multiplying.
  Button navigates to signup page
  (3 votes)
JosiahRamesar
Posted 9 years ago. Direct link to JosiahRamesar's post “Great video and now I rea...”
Great video and now I really now how to subtract decimals. Thank you?
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(3 votes)
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jacqueline.granados
Posted 7 years ago. Direct link to jacqueline.granados's post “i dont get this it dosent...”
i dont get this it dosent give me move edvice
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(3 votes)
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- Aditi
  Posted 2 years ago. Direct link to Aditi's post “What do you not get? Mayb...”
  What do you not get? Maybe if you have a different math resource, maybe you should go to that. I don't get all my questions answered on khan academy either.
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  (0 votes)
swagata.c16
Posted 3 months ago. Direct link to swagata.c16's post “Why is the video so short...”
Why is the video so short?It ended at
1:10
.
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Ian
Posted 5 months ago. Direct link to Ian's post “Ima only just be honest i...”
Ima only just be honest idk this
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🦋🪬Denise🪬🦋
Posted 3 months ago. Direct link to 🦋🪬Denise🪬🦋's post “We never got are gifts fo...”
We never got are gifts for khan for hitting one hundred.
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(2 votes)
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Video transcript

Let's try to subtract 9.57 minus 8.09. So try to pause this video and figure this out first before we work through it together. All right. Well, let's just rewrite it. Let's rewrite it. And when I rewrite it, I like to line up the decimals. This one it's a little intuitive. We have 8.09. Just like that, and now we're ready to subtract. And we want to subtract 9 hundredths from 7 hundredths. Well, we don't have enough hundredths up here so let's move over here. Let's see if we can do some regrouping so we always have a higher number on top. So over here we want to subtract 0 tenths from 5 tenths so we have enough tenths over here. So let's regroup. So instead of 5 tenths, I'm going to have 4 tenths, and then I'm going to give that other tenth, which is the same thing as 10 hundredths over here, so this becomes 17 hundredths. 17 minus 9 is 8. 4 minus 0 is 4. And then I have 9 minus 8 is 1. So this is going to be 1.48.

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