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Main content
Current time:0:00Total duration:4:19

Place value example: 42

Video transcript

what I want to do in this video is take this quantity represented by these I guess these greenish emerald looking bars where each bar represents one and try to represent them using the digits that we know the digits 0 1 2 3 4 5 6 7 8 9 and the way I'm going to do it is I'm going to group this into tens so I'm going to see how many tens I have and then essentially how many ones that I have left over so let's try to group this into groups of 10 so 1 2 3 4 5 6 7 8 9 let me actually I mess that up let's see 1 2 3 4 5 6 7 8 9 10 so that's one group of 10 right over there let me let me let me box that off so you know that that is 10 so that's one group of 10 now let's see let's see if I can get a few more groups of 10 in there 1 2 1 2 3 4 5 6 7 8 9 10 that's my second group of 10 right over there second group of 10 and now let's see it looks like I get several more groups of 10 here 1 2 3 4 5 6 7 8 9 10 so that's a third group of 10 it looks like I might even be able to get one more so that's my third group of 10 and then we have 1 2 3 4 5 6 7 8 9 10 so that's my fourth group of 10 fourth group of 10 right over here so I was able to fit in at least just this is one this is a 10 right over here this is another 10 right over here that's in the third 10 and then that's the fourth 10 so we could say that's 10 plus 10 plus 10 or all of this combined all of this combined is equal to 4 1 2 3 4 tens 4 tens but I'm not done I'm not done with the number still have one - I have two ones left over so this is a one so that's a one right over there and then this is another one so that's another one so I have two ones so this right over here that is two ones remember each of these little green bars we said represents a one so this whole number is what well it's going to be the four tens 1/10 2/10 3/10 is four tens plus the two ones so let me write that down so it is four tens plus plus two ones well what is that well if we use the number systems that we're used to representing we would say well look our number system gives us a way of representing that because the first place the first place this is the ones place so let me just in this blue color so this is the ones place so there we use one of the digits 0 1 2 3 4 5 6 7 8 9 to see how many ones we have and we have two ones and then the next place over to the left that's where we say how many tens we have that's where we say how many tens we have and we know how many tens we have we have four tens so the way that we would represent this in our number system is we would say that this is 4 tens and two ones and we call this right over here we call this 42 another way that you could think about this is four tens well for tens that's 10 plus 10 plus 10 plus 10 that's going to be 40 so but once again we're using our number system to represent this and then we have two ones and then we have two ones but I like to write it this way just to remind ourselves is four which represents four tens it also represents 40 because four tens is 40