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Percents from fraction models

Converting fractions to percentages is a valuable skill in math. To do this, rewrite the fraction with a denominator of 100, as "percent" means "per 100." For example, 7/10 equals 70/100, or 70%. Additionally, you can add percentages together, such as 100% + 80% = 180%.

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  • blobby green style avatar for user Vin
    ik the percent thing but i forget easliy and can get confused so just incase, can sombody explain this in a muck easier way? ;-;
    (23 votes)
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    • starky sapling style avatar for user amaya
      To change a fraction to a percent, all you have to do is change the denominator of the fraction to 100, and then figure out how you got there. For example, if I have 1/2, and I want to change it to a percent, I can change the denominator to 100, and then divide by my old fraction, aka just dividing 100 by 1/2, and then my answer (50) is my percent. Sorry if I confuse you more.
      (23 votes)
  • aqualine ultimate style avatar for user SoySausePellens
    To the only 6 people who see my posts, thank you for the support. Maybe in a couple years, we can reach 10!
    (36 votes)
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  • blobby green style avatar for user ¯\_(ツ)_/¯
    no way I got all of them right I think ¯\(ツ)
    (23 votes)
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  • blobby green style avatar for user clairelieuallen1
    what si 20% as a decimal
    (6 votes)
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  • aqualine ultimate style avatar for user mousehunter56
    At , , , and he tells us to pause the video. Why does he do that?
    (4 votes)
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  • starky tree style avatar for user Trevin
    how many time do you multiply
    (5 votes)
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  • male robot donald style avatar for user Jason Suarez
    What if it's not a square or a rectangle what if its a circle?
    (7 votes)
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  • marcimus purple style avatar for user Bri
    how do i take the test for this video without the video saying "not started yet" ?
    (9 votes)
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  • duskpin tree style avatar for user iArcherkylo
    ⬜⬜⬜⬛⬛⬛⬛⬛⬛⬛⬛⬛⬜⬜⬜⬜⬜
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    ⬜⬜⬜⬜⬜⬛⬛⬛⬜⬜⬛⬛⬛⬜⬜⬜⬜wah
    (6 votes)
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  • aqualine sapling style avatar for user FvrAri - :D - Get lost. 0.o
    wait how do you get the number to multiply by to turn the fraction to a percentage? if this was already said in this video, pls dont mind me I have ADHD. but atleast an answer?
    (4 votes)
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    • primosaur seed style avatar for user Ian Pulizzotto
      The idea is to rewrite the fraction as an equivalent fraction with denominator 100.

      To do this, figure out what number to multiply the denominator by, to get 100. Then multiply the numerator by the same number.

      Example: convert 3/5 to a percent.

      First figure out what number to multiply the denominator 5 by, to get 100. Note that 5x2=10, and 10x10 = 100. So 20 is the number we need to multiply 5 by, to get 100.

      Now multiply the numerator 3 by 20 to get 60.

      So 3/5 = 60/100 = 60%.
      The answer is 60%.

      Have a blessed, wonderful day!
      (5 votes)

Video transcript

- [Instructor] So we're told the square below represents one whole, so this entire square is a whole. And then they ask us what percent is represented by the shaded area, so why don't you pause this video and see if you can figure that out. So let's see. The whole is divided into one, two, three, four, five, six, seven, eight, nine, 10 equal sections, of which one, two, three, four, five, six, seven are actually filled in. That's the shaded area, so one way to think about it is 7/10 are shaded in, but how do we express this fraction as a percent? They're asking for a percent. Well remember, percent, it literally means per hundred. Cent, same root as the word 100. You see it cents or century, and so can we write this as per 100 instead of per 10? Well, seven per 10 is the same thing as 70 per 100, or 70%. And how did I go from 7/10 to 70 over 100? Well, I just multiply both the numerator and the denominator by 10. And once you do more and more percents, you'll get a hang of it. You'll say, "Oh, 7/10. "That's the same thing as 70 per 100, which is 70%." Let's do another example. Here, we're told 100% is shown on the following tape diagram, so just this amount right over here is 100%, and then they ask us what percent is represented by the entire tape diagram, so by this entire thing right over here. Pause this video and see if you can answer that. Well, one way to think about 100%, 100% is equivalent to a whole, and now we have three times as much as that for the entire tape diagram, so you could view this as three wholes, or you could say that's 100%. We have another 100% right over here. And then we have another 100% right over here, so the whole tape diagram, that would be 300%. Let's do another example. This is strangely fun. (laughs) Okay, and I'll see. It says the large rectangle below represents one whole. All right, so that's this whole thing is one whole. What percentage is represented by the shaded area? So pause the video and see if you can figure that out again. So let's just express it as a fraction first, so we have a total of one, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 squares. So out of those 20 squares, we see that six of them are actually shaded in. So 6/20, could we write that as per 100? Well, let's see. To go from 20 to 100, I multiply by five, and so if I multiply the numerator by five, I'll get the same value. Six times five is 30, so six per 20 is the same thing as 30 per 100, which is the same thing as 30%, which literally means per 100, so this is 30%. Let's do one last example. Here we are told each large rectangle below represents one whole, so this is a whole, and then this whole thing right over here is another whole. What percentage is represented by the shaded area? Again, pause the video. See if you can answer that. So this one, we've shaded in a whole, so that is 100%, and then over here, we have shaded in one, two, three, 4/5 of the whole. So 4/5, if I wanted to express it as per 100, what would it be? Well, five time 20 is 100, so four times 20 is 80, so 4/5, or 80/100, is filled out here. We could say 80 per 100, which is the same thing as 80%, so this right over here is 80%. So what percent is represented by the shaded area? Well, we have 100%, and then we have 80%, so we have 180%. It's more than a whole. If you have a percentage that is larger than 100%, you're talking about something that is more than a whole, and then we see that. We have a whole right over here, and then we have 80% more than that.