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# Subtracting a 1-digit number with regrouping

CCSS.Math:

## Video transcript

so we have the number 35 which is three tens because we have a 3 in the tens place so we have three tens and we have a five in the ones place so this is the ones place to the ones place in that same purple color this is the ones place and we see it represented here as five as five ones so 35 is the same thing as three tens and five ones three tens and five ones now what we want to do with this video is subtract eight from 35 and I encourage you to pause the video and try to figure out what 35 minus eight is all right so let's think about it we have five ones and we want to take away eight ones from there well we don't know how to take eight ones if we only have five we could take away five but then we're all out of ones so how do we take away eight well this is where regrouping is valuable because we don't we don't only have five squares we actually have we actually have 35 squares we have three groups of ten squares and then we have the five ones so what if we were to take one of these groups of ten right now it's in the tens place and we were to regroup it into the ones place so let's say we were to take this group right over here or take this group right over this group of ten and instead of instead of expressing it in the tens place let's put it in the ones place so let's move it over here and in the ones place it would be so one ten is the same thing as ten ones one two three four five six seven eight nine and ten so what just happened there I took away one of the tens so now I only have two tens and I took those ten and put them in the ones place so I have the original five ones and then I have the new ten that I just took from the tens place so five plus 10 is going to be 15 so I now have I now have 15 ones and now I can take away eight so if I take away eight now I would take away one two three four five six seven eight just to be clear I've taken I'm taking away eight and so what am I going to be left with I'm going to be left with - tens I'm going to be left with two tens and how many ones I have one two three four five six seven ones seven ones right over here now how do we do it if I didn't want to draw all of these things well you would have said all right I have five I have three tens and five ones this is where we started but I took one of those tens I took one of those tens away so I only have two tens now and I took those I took that group of ten and put in the ones place so it's ten ones so the five ones plus another ten ones give us 15 ones 15 ones and so you can say I have 15 ones minus eight ones is seven ones which we see over here one two three four five six seven so after doing the subtraction we have seven ones and then I have two tens left in the tens place so - ten seven ones 27