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Video transcript

in this video we're going to start thinking about what it means for something to be a multiple of a number so we're asked which of the following numbers is a multiple of nine so pause this video and see if you can figure that out alright now let's do it together and one way to think about a multiple a multiple is a number that you can get to by multiplying the number in this case nine by a whole number so we could figure out the multiples of nine by skip counting that's one way to do it so you could go from nine and then you add nine to that you get to 18 the add nine to that you go to 27 yeah add nine to that you are going to get to 36 yet 9 to that 45 nine to that 54 add nine to that 63 add nine to that you get 72 add nine to that you get to 81 and we could keep going but to figure out whether these are multiples you really just have to say hey are any of these numbers in this list now if one of these numbers are larger than 81 we would have to keep going to see it's included but we can see that 46 sits between two multiples of 9 46 that sits closer to 45 but it sits in there it sits between two multiples so that's not going to be a multiple another way to think about it is for something to be a multiple if you divide by nine you're not going to get a remainder but if you divided 46 by nine you are going to get a remainder you're not going to be able to divide nine into it evenly so I am just going to I'm going to take that one out of the contention 77 is right over here's between 72 and 81 once again it's between two multiples but not a multiple 39 is between 36 and 45 so not a multiple between two multiples rule that out and we can see very clearly that 18 is a multiple if I was doing this on my own I would just maybe be skipped counting in my head I'll be going nine all right I don't see a 918 oh I see an 18 there there you go especially if I'm only going to pick one choice let's do another example which of the following shows only multiples of eight so pause this video and think about that alright well I could do a choice by choice here so let's see this first one is for a multiple of eight well four is can divide into eight we could say that eight is a multiple of four but four is not a multiple of eight what a whole number am I going to multiply 8 by to get to four so we can rule this out and you can think about what's what they're showing here these are actually multiples of four not multiples of eight we can skip count here 4 8 12 16 20 24 28 these are multiples of 4 not multiples of 8 some of the multiples of 4 are also multiples of 8 8 is a multiple of 8 16 is a multiple of 8 24 is a multiple of 8 but not all of the multiples of 4 are multiples of 8 and I think you might be seeing a little pattern here which ones are multiples of 8 now what about this choice right over here 16 is 8 times 2 24 is 8 times 3 32 is 8 times 4 40 is 8 times 5 in fact we could skip count 8 + 16 24 32 40 then 48 56 so on and so forth but these are all multiples of 8 so I like this choice and then over here 1 2 4 & 8 well these are showing numbers that can be divided into eight without a remainder you could think of them as factors of 8 you could say hey I could multiply 1 times 8 to get 8 I could multiply 2 times 4 to get 8 but these are not multiples of 8 what what whole number can I multiply 8 by to get 1 or to get 2 or to get 4 in general your multiples of a number are going to be are going to be that number or larger that was about to say the got number or multiple sub but then I realize I can't use multiples to define multiples it would be that number or larger numbers than it and it would have to and if you were to skip count with that number you would hit all of the multiples