Video instructions and help with filling out and completing How Form 944 Pr Fractions

Instructions and Help about How Form 944 Pr Fractions

In this video we're going to focus on how to add subtract fractions how to multiply divide them how to convert improper fractions to mixed numbers basically almost everything you need to know about fractions so let's begin so let's say if you want to add these two fractions 7 over 5 and 1 over 4 how would you do it well here's one quick and simple technique you can multiply 5 & 4 which will give you 20 and then next multiply 7 times 4 which is 28 and then add that to 5 times 1 which will give you 5 so 28 plus 5 that's 33 and divided by 20 let's try another example so whether you're adding or subtracting you can use the same technique so let's say if you want to subtract these two numbers 3 / 4 - 2 / 7 multiply the two numbers on the bottom 4 times 7 that's 28 and 3 times 7 is 21 and then 4 times 2 is 8 but there's a minus sign between them so in this case this is going to be 13 over 28 but now that's not the only way that you can combine two fractions now we're going to go over the same problem but using a different technique now notice that you have a 4 here what you can do is multiply this fraction top and bottom by 4 and for this one multiply the first fraction top and bottom by this number 7 3 times 7 is 21 and 7 times 4 is 28 a time well 2 times 4 is 8 and that's also 28 and so you can get the same answer now once you have the same denominator you can now add the denominators in this case of trakt 21 minus 8 that's 13 so that's another technique in which you can get the same answer if you want to add or subtract two fractions but now let's say if you want to combine three fractions let's say if you have 1 over 3 plus 2 over 5 minus 3 over 4 now the first technique won't really be useful in this example or it might be quite confusing but the second technique will be very helpful what we need to do is figure out the least common denominator which is basically all of them we need a 3 a 5 and a 4 now this fraction has a 3 but it's missing the 5 and the 4 so we're going to multiply top and bottom by 4 and by 5 at the same time now for this fraction it has the 5 but it's missing 2 3 & 4 so we're going to multiply top and bottom by 3 and by 4 and for this one we need to add a 5 and we'll miss in we have a 4 ready we'll miss in the 3 the goal is to make sure that the denominator of every fraction is identical so 5 times 4 is 20 and 20 times 3 if 2 times 3 is 6 20 times 3 is 60 every fraction will have the same denominator and that is 60 so now we're going to do is a multiply the numerators 5 times 4 is 20 and for the next one let's see 4 times 2 is 8 and then 8 times 3 that's 24 3 times 5 is 15 and 15 times 3 that's 45 or you can do 3 times 3 which is 9 9 times 5 is 45 either way you get the same answer now if we have the first two numbers 20 plus 24 that's 44 and then if we subtract 44 by 45 we get negative one so that's the answer for this example it's negative 1 over 60 but for the sake of practice let's try another example so let's say if we wish to add 2 over 3 plus 1/2 minus 3/4 so the common denominator we need a 3 a 2 and a 4 so the common denominator is 3 times 2 times 4 which is 24 so for this fraction it's the first one it's missing a 4 and a 2 so let's multiply top and bottom by those numbers 4 & 2 okay this one has a 2 but it's missing 2 3 & 4 so let's multiply top bottom by 3 & 4 whatever you do to the top you have to do to the bottom and this one it has the 4 but it's missing these two so we know we have a common denominator of 24 okay so now let's do some math 2 times 2 is 4 times 4 that is equal to 16 here 4 times 3 that's 12 and 3 times 3 is 9 times 2 that's 18 so 16 plus 12 that's 28 and 28 minus 18 is 10 so we get 10 over 24 but we have a fraction in which both numbers are even which means that we can reduce this fraction if we divide top modern by 2 and we can get this half of 10 is 5 and half of 24 is 12 so the final answer for this example is 5 over 12 so that's how you can add or subtract 2 or 3 fractions let's try this one let's say if you have five divided by X plus 2 over 3 so the common denominator is basically these two combined 3x so let's multiply this by X and this side by 3 so then 3 times 5 is 15 and here we just get 2x so at this point once you have the same denominator you can combine this into a single fraction but we can't add 15 and 2x because they're not like terms so this is the final answer for this example let's try another example in which we have variables so let's say if we wish.