 In this video, we'll look at what are percentages. First, it's just the meaning of the word percent. It's broken up into two root words. One is per, which means buy or four, or in this case, you know, divide by. So for example, you could have $11 per hour or $11 for one hour. And then cent or cent in French means a hundred. So per, buy, cent, a hundred, or four, one hundred. So a percent is always a fraction out of a hundred. So 75% is 75 per 100. A percent always has a symbol, which you've probably seen before, and that's the percent sign. It has the slash with the two circles top and bottom. A percent always represents a fraction where the denominator is always 100. So 45% can be written as 45 over 100, or the decimal is 0.45. You can see where the decimal would come from if you do the long division of 45 divided by 100. You can also take a percent as a fraction, 45 over 100, and reduce it to, in this case, 9 over 20 by dividing top and bottom by 5. Fractions and percentages are very closely related because any equivalent fraction you can then make to something over 100. So you can represent the same part of a whole using a percent pretty easily. So why would you convert to a percentage? Well, it's easier to compare. It's a very consistent scale, and it's very easy to relate to. So for example, you may have a few different tests throughout the semester. Maybe the first one was out of 20, then out of 25, 50, 35, and 43. These fractions might not mean too much to you, but once you convert them to a percentage, you get 90 out of 100, 76 out of 100, 88, 83, and 84. Or the equivalent 90%, 76%, 88%, 83%, 84%. So we can automatically see that the 76% was our lowest, and our first test, the 90, was our highest. When converting a percent to a decimal, we're basically taking the decimal point, which is at the end of the 7, and dividing by 100 to move it two places to the left. So if we take that fraction, 37 over 100, we're dividing top and bottom by 100 to get 0.37 over 1, which is the decimal 0.37. Going from decimal to a percent, we basically take the decimal, which in this case is right before the 5, and we multiply by 100 to move it two places to the right. So if you take the fraction 0.59 over 1, now we're going to multiply instead of divide by 100, top and bottom, and we get 59 over 100, which is 59%.