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Цаг: 0:00Нийт үргэлжлэх хугацаа:6:05

last video we get a little bit of practice adding decimals that involved tenths now let's do slightly more complicated examples so let's say we want to add four to five point seven or we could read the second number as five and seven tenths pause this video and see if you can do this so the way that my brain tries to tackle this is I try to separate the whole numbers from the tenths so you can view this as being the same thing as four plus five plus seven tenths all I did here is I broke up the five and seven tenths into five plus seven tenths and the reason why my brain likes to do that is because I can then say okay four plus five that's just going to be equal to nine and then I just have to add the seven tenths this is going to be nine and seven tenths which I can rewrite this is going to be equal to nine and seven tenths and nine and seven tenths I could write as nine point seven and even though in future videos we're going to learn other ways of adding decimals especially larger more complicated decimals this is still how my brain adds four plus five point seven especially if I need to do it in my head I say okay 4 plus 5 is 9 and then I have that seven tenths so it's going to be nine and seven tenths or nine point seven now let's do another example where both numbers involve a decimal so let's say I want to add six point three to seven point four so six point three plus seven point four once again pause this video and try to work through it on your own well my brain does it the same way I break up the whole numbers and the decimals and once again there's many different ways of adding decimals but this is just one way that seems to work especially for decimals like this so we could view this as six and three tenths so I'm breaking up the six point three is six and three tenths into six plus three tenths +7 and 4/10 7 plus 4 tenths and then this you can view as so you could view this as 6 plus 7 6 plus 7 plus plus 3 tenths plus 3 tenths plus 4 tenths plus 4 tenths so if you add the ones here you have 6 ones and 7 ones that's going to be equal to 13 and then 3 tenths and 4/10 well if you have 3 of something then you add 4 of that that's going to be 7 tenths and we would write 7 tenths is 0.77 in the tenths place and then what's 13 plus 7 tenths well that is going to be 13 this is going to be equal to thirteen point seven thirteen point seven and we are done let me do one more example that will get a little bit a little bit more involved so let me delete all of these so let's say I wanted to add six point three two and I'm going to add that to two point two point nine pause the video and see if you can figure this out well let's do the same thing this is going to be six and three tenths so 6 plus 3 tenths plus two plus 9/10 or you could view this as 6 plus 2 so I'll put all my ones together 6 plus 2 and then I'll put my tents together plus 3 tenths plus 3 tenths plus 9 tenths plus 9 tenths and so the 6 plus 2 is pretty straightforward that is going to be equal to 8 and now what's 3/10 plus 9 tenths this is going to get a little bit interesting 3 tenths plus 9 tenths and I can write it out I could say this is 3 tenths this is 9/10 well three tenths plus 9/10 is equal to twelve tenths this is going to be twelve tenths but how do we write twelve tenth as a number well 12 tenths is the same thing as 10 tenths plus two tenths and the reason why I broke it up this way ten ten is one hole so this is going to be equal to one so when you add these two together it's twelve tenths which is the same thing as 1 & 2 tenths so 1 plus 2 tenths or let me just write it that way so this I can rewrite as plus 1 plus 2 tenths and then I think you see where this is going I could add the 8 and the 1 and I get 9 and 2 tenths so 9 & 2 tenths so it's going to be nine point two now the reason why this one was a little bit more interesting is I added the ones I got six plus two is eight but then when I added the tenths I got something that was more than a hole I got what I got twelve tenths which is one and two tenths and so I added one more hole to the eight to get nine and then I had those two tenths left over and this is really good to understand because in the future when you're adding decimals you'll be doing stuff like carrying from one place to another and this is essentially what we did when we added the three tenths plus the nine tenths we got twelve tenths until we added an extra hole and then we had the leftover to ten hopefully that makes some sense