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Math Antics- Adding & Subtracting Fractions

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in this video we're going to learn the basics about how to add fractions on a lot of math books will teach you how to add fractions before they teach you out of motor but here at Math Antics we think you should learn the other way around you remember how easy it is to multiply fractions right you just multiply the top numbers together and you multiply the bottom numbers together and you have your answer so you might be wondering can't we just do that with addition to can't we just add the top numbers together and add the bottom numbers together and get our answer all right let's try it and see but I got a bad feeling about this let's try adding 1/2 to 1/2 so if we added the chart first we get to and if we added the bottom numbers would get for but that can't be right because 2/4 simplifies to 1/2 and if you add 1/2 and 1/2 you should get a whole bottom half Westbrook some sort of Matthew okay here's what we did wrong it turns out that there's some important math rules called order of operations that say you have to do multiplication division before you do addition and subtraction now because fractions or just division problems if you just added the top numbers and added the bottom numbers you would be breaking those rules because you would be doing the addition before the division what are we going to do instead we'll fortunately there's a trick that lets his work but there's a catch it only works for fractions that have the same bottom numbers if fractions have the same bottom numbers we can add them by just adding the numbers together and keeping the same bottom number in our answer for example to add 1/2 and 1/2 we just add the top numbers and OnePlus One gives us but we don't add the body we just use the same phone number in the answer which is 2 so 2/2 is a whole fraction and that makes sense because if you add 1/2 and 1/2 you get a whole let's see if you more. what does 15 / 16 + 2 / 16 again since the bottom numbers are the same it's easy to add these fractions together to equal 7 and that's the top number of her answer we just keep 16 as the bottom number of our answer so 5/16 + 2/16 equals 7 over 16 pretty easy huh but what about subtracting fractions does that work the same way if the bottom numbers are the all you have to do is subtract the top numbers and keep the same bottom number in your answer there's an example of subtracting fractions with the same bottom number 5 / 9 - 2 / 9 Bruce we subtract the top numbers 5 - 2 equals 3 then we just write the same bottom number in her answer 9 so 5/9 - 2/9 is 3/9 adding and subtracting fractions with the same bottom numbers is easy and there's a special name for prom it's like this it's called adding or subtracting like fractions a teacher once told me that they're called like fractions because the bottom numbers are the same or a like I think it's cuz they secretly like each other just kidding but seriously why fractions are easy to add with a trick we just learn but what happens if you want to add two unlike fractions what do you do if you have fractions with different bottom numbers unfortunately the only way we can add unlike fractions without doing the division first is the change them so that they do have the same bottom numbers in other words we need to change our unlike fractions into like fractions so we can just use our trick in math language that's called finding a common denominator and remember that it did nominator is just fancy math word for the bottom number of a fraction and common just means that they're the same so how do we find a common denominator so that we can add or subtract unlike fractions that's what we're going to learn in the next video before you move be sure to do the exercises for this section learn more at Math Antics.

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Math Antics- Adding & Subtracting Fractions

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