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(1) Frac Add / sub basic

Added Oct 11, 2015 •

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1st video to help you to understand how to add and subtract fractions with alike denominators

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in this video we're going to learn the basics about how to add directions know a lot of math books will teach you how to add fractions before they teach you how to multiply them but here at Math Antics we think you should learn the other way around you remember how easy dish 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 why 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 her answer will all right let's try it and see but I got a bad feeling about this let's try adding 1/2 to 1 half so if we added the top number so we get to and if we added the bottom numbers would get for but will that cam do right because too old for simplifies to 1/2 and if you add 1/2 and 1/2 you should get a whole not half Westbrook some sort of Matthew I'm out of here  okay here's what we did wrong it turns out that there I'm important math rules called order of operations that say you have to do multiplication and division before you do addition and subtraction Mel because Skins are just division problems if you just added the top numbers and added the bottom numbers you'd be breaking those rules because you would be doing the addition before the division so what are we going to do instead will fortunately there's a trick that lets his work around the order of operation rules and add fractions without dividing but there's a cat it only works for fractions that have the same bottom numbers the trick is if fractions have the same bottom numbers we can add them by just adding the put 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 bottom numbers we just use the same bottom 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 let's see if you more examples like this one 5/16 + 2 / 16 again since the bottom numbers are the same it's easy to add these fractions all we do is add the top numbers together by plus two equals 7 and that's the top number ever answer when we just keep 16 as the bottom number of our answer so 5/16 + 2 / 16 equals 7 over 16 pretty easy huh what about subtracting fractions does that work the same way yep if the bottom numbers are the same all you have to do is subtract the top numbers and keep the same bottom number in your answer here's an example of subtracting fractions with the same bottom number 5/9 - 2/9 first we subtract the top numbers five- do 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 as easy and there's a special name for problems like this it's called adding or subtracting like fractions once told me that they're called like fractions because the bottom numbers are the same or alike but I think it's cuz they secretly like each other just kidding but seriously why Corrections are easy to add with the trick we just learned 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 to change them so that they do have the same bottom numbers in other words we need to change 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 a denominator is 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 but before you move on be sure to do the exercises for this section  learn more Math Antics.

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(1) Frac Add / sub basic

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