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Current time:0:00Total duration:2:35

CCSS.Math:

what we want to do in this video is get some practice estimating multi-digit division problems so here we're asked to estimate 794 divided by 18 now if you wanted to get the exact answer you'd probably have to do so in fact you would have to do some long division or maybe use a calculator but the whole point here is to get some practice estimating so pause this video and try to see if you can figure this out without even using any pencil or paper all right so now let's do this together so I'll tell you what my brain does my brain says that look 794 is awfully close to 800 and then 18 is close to 20 and so I would say this is going to be roughly the same thing as 800 it's going to be roughly equal to 800 divided by 20 it's going to be exactly equal no but these are the numbers closest to the numbers there that it's easy for me to divide in my head so for example I could I would then say if I was just doing this purely in my head I would say well a hundred divided by 20 is five so 800 divided by 20 is equal to 40 or another way to think about it 800 over 20 if we divide the numerator and denominator by 10 it's the same thing as 80 over 2 which is equal to 40 so 794 divided by 18 definitely isn't exactly 40 but it's going to be close to 40 and especially of these choices right over here it's definitely gonna be much closer to 40 than 84 or definitely 400 so we're gonna go with that let's give it get another example here make sure we get enough practice so once again we are asked to estimate 722 divided by 68 and so why don't you have a go at it pause the video and try to see if you can figure out what it is and try to do it in your head well what I would do in my head I would say well look 722 this is awfully close to 768 is awfully close to 70 and then this is quite straightforward to do in your heads 700 divided by 70 is going to be equal to 10 and good for us there is a choice here that is awfully close to what we up proximate it now if you don't find your exact answer here that's okay because it remember it's an approximation you should find the answer that is closest to what you estimated but whoever wrote this question had a very similar thought process they said okay seven or twenty two pretty close to 768 pretty close to 70 and so it's going to be approximately equal to seven hundred divided by seventy