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Converting percents to decimals & fractions example

Sal writes 18% as a decimal and as a fraction. Created by Sal Khan and Monterey Institute for Technology and Education.

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  • mr pants teal style avatar for user Connor Eason
    how do make percents into fractions
    (35 votes)
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    • blobby green style avatar for user Tim Daugherty
      Hi Connor - I like to think of a "percent" as a "fraction of 100". For example, 80% is the same thing as the fraction 80/100.

      Once you have your fraction of 100, you can then simplify it. In this case, both 80 and 100 are divisible by 10, so 80/100 would equal 8/10. And since in this fraction, both 8 and 10 are divisible by 2, you can simplify it to 4/5. So that's how you can convert a percent into a fraction.
      (45 votes)
  • starky sapling style avatar for user eman.150839
    um does anyone answer these anymore?
    (17 votes)
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  • spunky sam blue style avatar for user SamsOreoCookies
    Honestly, I used to get so worried when trying to do percentage problems. But once I actually do them now, its really simple!
    (19 votes)
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  • starky seedling style avatar for user Hayley Parente
    What would 4% equal? I'm stuck. (Don't judge me I am horrible at these 😂)
    (14 votes)
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  • blobby green style avatar for user Miriam Smith-Elliott
    How to change .08 to a fraction
    (7 votes)
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  • duskpin seed style avatar for user Korinn Leonard
    can't you just put 18 over 100 then simplify to get your answer?
    (5 votes)
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  • starky tree style avatar for user hianit18
    What if, when you are trying to convert a fraction to a percentage but the denominator is not a factor of 100? How do you do it?
    (3 votes)
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    • purple pi purple style avatar for user Sam De Laurentis
      The following assumes you are asking to perform all calculations manually.
      One way to do it is to perform long division to convert the fraction to a decimal, then you can multiply the decimal by 100 to get a percentage. This assumes you know how to perform long division with decimals in the quotient and the dividend.
      For example, if the fraction is 5/16, you could use long division to get a decimal answer to 5 divided by 16 and then multiply that by 100.
      Another method is to multiply the fraction by 100 first to get 500/16 then perform long division to get a straight percentage.
      If you don't know how to do long division with decimals in the quotient and dividend then using a calculator is probably the best option. (I would use a calculator in this case anyway even though I know long division)
      Using a calculator it is as easy as entering 5 / 16 and either pressing the percent key or multiplying by 100.
      (13 votes)
  • winston baby style avatar for user Drake
    at Write 18% as a decimal and as a fraction in simplest form. So let's do it as a decimal first. So 18% is the same thing as 18 per 100, or 18 per cent. I'm actually separating out the percent, it's only going to be one word, but I'm writing it as, literally, per cent. Cent means the same thing as 100. So this literally means 18 per 100. Actually, I said I would do the decimal first, but we can start putting it into a fraction first. 18 per 100 as a fraction literally means 18/100. We're literally doing the fraction first. This literally means 18 per 100, or 18 hundredths. From here we can go straight to a decimal or we could do this fraction in simplest form. Let's do the decimal first, just because that's actually what I said I would do first. Let's do that first. This is the same thing as 18 hundredths. And we know how to write that in decimal form. It's 0.18. You could view this as 1 tenth and 8 hundredths, which is the same thing, or 10 hundredths and 8 hundredths, which is 18 hundredths. So this is written in decimal form. And if we write it as a simplified fraction, we need to see if there is a common factor for 18 and 100. And they're both even numbers, so we know they're both divisible by 2, so let's divide both the numerator and the denominator by 2. So we have 18 divided by 2 over 100 divided by 2. And we're going to get 18 divided by 2 is 9. 100 divided by 2 is 50. And I don't think these guys share any common factors. 50 is not divisible by 3. 9 is only divisible by 3 and 1 and 9. So this is the fraction in simplest form. So we have 18% is the same thing as 0.18, which is the same thing, in simplest form, as 9/50. Now, I went through a lot of pain here to show you that this really just comes from the word, from percent, from per 100. But if you ever were to see this in a problem, the fast way to do this is to immediately say, OK, if I have 18%, you should immediately say, anything in front of the percent-- that's that anything, whatever this anything is-- it should be equal to that anything. In this case it's 18/100. And another way to think about it, you could view this as 18.0%. I just added a trailing zero there, just so that you see the decimal, really. But if you want to express this as a decimal without the percent, you just move the decimal to the left two spaces. So if we move the decimal to the left two spaces, one, two, this becomes 0.18. Or you could immediately say that 18% as a fraction is 18/100. When you put it in simplified form, it's 9/50. But you should also see that 18/100, and we have seen this, is the exact same thing as 18 hundredths, or 0.18. Hopefully, this made some connections for you and didn't confuse you.
    (6 votes)
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    • area 52 purple style avatar for user aspen !
      Let's say that I've got 2 Chuck Norrises, or maybe it's Chuck Norri. And to that I am going to add another 3 Chuck Norrises. So I'm going to add another 3 Chuck Norrises. And this might seem a little bit obvious, but how many Chuck Norrises do I now have? Well, 2 Chuck Norrises, we can represent this as literally a Chuck Norris plus a Chuck Norris. So let me do that, a Chuck Norris plus another Chuck Norris, 2 Chuck Norrises. You could also do this 2 times Chuck Norris, and this is just another way of representing it. And 3 Chuck Norrises-- you could do that as a Chuck Norris plus a Chuck Norris plus another Chuck Norris. And so we would have a grand total-- and this might be very simple for you. But you would have a grand total of 1, 2, 3, 4, 5 Chuck Norrises. So this would be equal to 5 Chuck Norrises. Now, let's get a little bit more abstract here. Chuck Norris is a very tangible thing. So let's go to a little bit more of traditional algebraic notation. If I have 2x's and remember, you could do this as 2x's or 2 times x. And to that, I would add 3x's How many x's do I have? Well, once again, 2x's, that's 2 times x. You could do that as an x plus an x. We don't know what the value of x is. But whatever that value is, we can add it to itself. And then 3x's are they're going to be that value. Let me do that in that same green color. 3x's are going to be that value plus that value plus whatever that value is. And so how many x's do I now have? Well, I'm going to have 1, 2, 3, 4, 5 x's. So 2x plus 3x is equal to 5x. And if you think about it, all we really did-- and hopefully, you conceptually get it-- is we just added the 2 numbers that were multiplying the x. And these numbers, the 2 or the 3, they're called coefficients. Very fancy word, but it's just this constant number, this regular number that's multiplied by the variable. You just added the 2 and the 3, to get your 5x. Now, let's think about this a little bit more. Let's go back to this original expression, the 2 Chuck Norrises plus 3 Chuck Norrises. Let's say, to that, we were to add to some type of a-- let's we were to add 7 plums over here. So this is my drawing of a plum. So we have 7 plums plus 2 Chuck Norrises plus 3 Chuck Norrises. And let's say that I add another 2 plums. I add another 2 plums here. So what this whole thing be? Well, I wouldn't add the 7 to the 2 to the 3 plus the 2. We're adding different things here. You have 2 Chuck Norrises and 3 Chuck Norrises, so they're still going to simplify to 5 Chuck Norrises. . And then we would separately think about the plums. We have 7 plums, and we're adding another 2 plums. We're going to have 9 plums. Plus 9 plums, so this simplifies to five Chuck Norrises and 9 plums. Similarly, over here, instead of just 2x plus 3x, if I had 7y plus 2x plus 3x plus 2y, what do I now have? Well, I can't add the x's and the y's. They could very well represent a different number. So all I can do is really add the x's. And then I get the 5x. And then, I'd separately add the y. If I have 7y's and to that I add 2y's, I'm going to have 9y's. If I have 7 of something and I add 2 of something, I now have 9 of that something. So I'm going to have 9y's. So you add that. Do that in a different color. You add this and this. You get that. You add the x's. You get that right over there. So hopefully, that makes a little sense. Actually I'll throw out one more idea. So given this, what would happen if I were to have 2x plus 1 plus 7x plus 5? Well, once again, you might be tempted to add the 2 plus the 1, but they're adding different things. These are 2x's. This is just the number 1. So you really just have to add the x's together. So you're going to say, well, I got 2x's. And I'm going to add 7x's to that. Well, that means I now have 9x's. And then, separately, you'd say, well, I've got just the abstract number 1. And then I've got another 5. 1 plus 5 is going to be equal to 6.
      (6 votes)
  • male robot hal style avatar for user Owen Sterling
    what 22/25 of per cent of %
    (7 votes)
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  • primosaur seedling style avatar for user flyhighstem
    Hey, does anybody use Khan Academy anymore? I feel like I'm the only person in the whole world using it. If you use Khan Academy, then please tell me! I feel weird, because all of these comments and answers are from years ago and no new ones have been written lately. Is Khan Academy a rogue website that nobody's using nowadays? Anybody here? 😕👽🤖😨🤢!
    (5 votes)
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Video transcript

Write 18% as a decimal and as a fraction in simplest form. So let's do it as a decimal first. So 18% is the same thing as 18 per 100, or 18 per cent. I'm actually separating out the percent, it's only going to be one word, but I'm writing it as, literally, per cent. Cent means the same thing as 100. So this literally means 18 per 100. Actually, I said I would do the decimal first, but we can start putting it into a fraction first. 18 per 100 as a fraction literally means 18/100. We're literally doing the fraction first. This literally means 18 per 100, or 18 hundredths. From here we can go straight to a decimal or we could do this fraction in simplest form. Let's do the decimal first, just because that's actually what I said I would do first. Let's do that first. This is the same thing as 18 hundredths. And we know how to write that in decimal form. It's 0.18. You could view this as 1 tenth and 8 hundredths, which is the same thing, or 10 hundredths and 8 hundredths, which is 18 hundredths. So this is written in decimal form. And if we write it as a simplified fraction, we need to see if there is a common factor for 18 and 100. And they're both even numbers, so we know they're both divisible by 2, so let's divide both the numerator and the denominator by 2. So we have 18 divided by 2 over 100 divided by 2. And we're going to get 18 divided by 2 is 9. 100 divided by 2 is 50. And I don't think these guys share any common factors. 50 is not divisible by 3. 9 is only divisible by 3 and 1 and 9. So this is the fraction in simplest form. So we have 18% is the same thing as 0.18, which is the same thing, in simplest form, as 9/50. Now, I went through a lot of pain here to show you that this really just comes from the word, from percent, from per 100. But if you ever were to see this in a problem, the fast way to do this is to immediately say, OK, if I have 18%, you should immediately say, anything in front of the percent-- that's that anything, whatever this anything is-- it should be equal to that anything. In this case it's 18/100. And another way to think about it, you could view this as 18.0%. I just added a trailing zero there, just so that you see the decimal, really. But if you want to express this as a decimal without the percent, you just move the decimal to the left two spaces. So if we move the decimal to the left two spaces, one, two, this becomes 0.18. Or you could immediately say that 18% as a fraction is 18/100. When you put it in simplified form, it's 9/50. But you should also see that 18/100, and we have seen this, is the exact same thing as 18 hundredths, or 0.18. Hopefully, this made some connections for you and didn't confuse you.