### Video instructions and help with filling out and completing Who Form 8815 Subtract

Instructions and Help about Who Form 8815 Subtract

Get a welcome to the take math Channel what we're gonna be having a look at in this video is a way of subtracting fractions from one another fractions with unlocked and on liners different bottom numbers and we're gonna be looking at how to do this pretty much instantly okay so it's a it's without all that messy working out that you often get with fractions and once your work out how to do this trick look that's a really really great and easy method of doing it as well okay so what about I'll give you an example and I'm gonna answer this one fairly quickly but you see we can answer it while I'm busily writing it down so 3/4 take away 1/2 now the answer that you should get with this is as follows you should get 2 over 8 look and you can possibly then simplify you can possibly you can simplify this further into 1/4 but I'm gonna leave them unsimplified from the minute okay so did you get that answer pretty much straightaway if not I'll tell you what I'm gonna show you how to do this pretty much right away okay and I did that exact speed so I'll show you how to do this now as follows this is how we do it so first off I'm gonna show you how to get the bottom number they're not gonna show you how to get the top them a bit once you start getting used to these I tend to start working at the top number first and in the bottom number okay so the bottom number is pretty much easy it's our 4 times 2 okay so you just multiply these two numbers you're gonna get your bottom number which is 8 okay that's the first one to get this number here this top number what we do is as follows we're gonna start and this is a critical part here we have to start on this left hand side and what we're gonna be doing is we're in a multi point multiplying the top number on the left hand side by this number and then this number by this number and we're gonna be taking them away from 1 let's say 3 times 2 is 6 1 times 4 is 4 another 6 take away 4 to get my answer which is 2 weights and it's really really critical that you actually do it in that order that you don't go this one by this one take away this one by this one because I was joined up with 4 take away 6 and you the wrong answer so we start in the top left-hand corner and we're multiplying this way and then this way taking answers away that's pretty easy technique a anyway what about I'll give you another example here so it's a nice easy one what about 1/2 take away 2/5 so I'm gonna do the work yet with you here so let's first off get this bottom number to get that what do we do we multiply these numbers so 2 times 5 is 10 then what we did is we start in this top left corner 1 times 5 is 5 2 times 2 is 4 okay we're taking that away so 5 take away 4 we get the answer of 1 so my answer is 110 now what I start to do it after what were these as I'll start to actually work out this top number first because that's typically the order in which we say we say it's 1/10 so while you're busily working this one out then you can automatically work this one out for the bottom okay so and that's the reason I'd start doing it in that order but you know whichever whichever way you like this I tell you what we'll do it one way like this now so 4/5 where I work at the top number so 4/5 take away 2/3 and what does this equal so this is the last bit of working and I'm gonna show you then I'm gonna start just doing them in a head so 4 times 3 is 12 and then 2 times 5 is 10 gonna be taking that away ok so 12 take away 10 it's 2 and then 5 threes a 15 so we got to 15 how'd you go with that you might want to be pausing this while you're doing this and because you know you might take a little bit longer to start off with these okay a couple more of these so what about two-thirds and from this we're going to take away one quarter so let's start doing this without that better working out you might pause this and do the working yet okay maybe you will pausing okay but I might do this without doing all that little working out down here now I'm just gonna start going straight to the answer so what's going on in my head while we're doing this is eight take away 3 which is 5 3 times 4 is 12 how'd you go with that pretty good good ok last question here 4/5 takeaway half and once again we can start splitting this answer straight in because we're going 8 take away 5 which is 3 yeah 4 times 2 is 8 take away 1 times 5 which is 5 it's 3 and a number here and on the bottom is 2 times 5 which is 10 it's very tense ok pretty cool right a really really easy method of doing these and look yeah but look at that there's no trying to change two common denominators and all that sort of deal you know get that bottom number the same and there's no multiple lines of working out it's pretty much there now look what we also haven't dealt with here and I know.