If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:5:06

Video transcript

we've got 9601 - 8023 and immediately when we try to start subtracting in our ones place we have a problem this three is larger than this one and we also have that problem in the tens place this two is larger than this zero so we're going to have to do some type of borrowing or regrouping and so the way I like to think about it I like to go to the first place value that has something to give obviously the tens the tens place is in no position to give anything to the ones place it needs things itself and so we're gonna go to the hundreds place and the hundreds place has an abundance of a value that it can regroup into the tens and ones place this six right over here represents 600 so why don't we take 100 from that 600 so then this will become 500 and then give that hundred over to the tens place now if we give a hundred to the tens place well how would I represent that in the tens place well I have zero tens and now I'm going to give a hundred 100 is the same thing as ten tens so I'm not going to have it's going to be zero plus a hundred a hundred in the tens place is just ten so let me write it this way so this right over here is now going to be rewritten as ten now you might be saying wait wait wait wait what's going on here Sal you took a hundred from the hundreds place that's why it became five hundred now why did this become ten and not a hundred now remember this is ten tens so this is still representing a hundred you have not changed the value of this top number before the value was nine thousand plus six hundred plus one now it's nine thousand plus 500 plus 110 tens is one hundred plus one I have not changed the value here now we're still not done yet we don't want to just subtract because we still have the problem with the ones place the ones placed is still not hat still doesn't have enough a value now the good thing is we've given some value to the tens place so why don't we take 10 from the tens place so if you have ten tens and you take 110 away you're going to be left with nine tens or ninety then we can take that 10 and give it to the ones place so let's do that you take that 10 we just took from there you give it to the ones place you now have 11 here and now we are ready to subtract 11 minus 3 is 8 9 minus 2 and this is really 90 minus 20 is 70 but in the tens place we represent that as a seven five hundred minus zero hundred is five hundred represented as a five in the hundreds place nine thousand minus eight thousand is one thousand and we're done and just to make things really clear I'm going to redo this problem now but with things expand it out so this first number is nine thousand nine thousand plus 600 plus 600 plus zero tens plus zero tens plus one plus one and this number right here we're subtracting eight thousand we're subtracting zero hundreds we're subtracting two tens which is 20 subtracting 20 and subtracting three ones so I've just rewritten this exact same statement but it's the the regrouping and the borrowing is going to be a little bit clearer now so the same exact thing we said hey we can't subtract the 3 from the 1 or the 20 from the zero we have a lot of value right over here in the 600 so why don't we take a hundred from that so this becomes 500 and we give we give that hundred to the tens place so this this becomes this becomes one hundred notice this the value has not changed this is nine thousand plus 500 plus 100 plus one that's the same thing as nine thousand plus 600 plus one we've just put the value in different places and here we've explicitly written 100 but when we represented it in the tens place ten tens is the same thing as 100 now we aren't done regrouping just yet we want to give some value to the ones place so we can take 10 from the tens place and this becomes a 90 and give that 10 to the ones place 10 plus 1 is 11 so notice I did the exact bar throwing the exact regrouping that I did here I just represented it a little bit different this 500 was represented by a five in the hundreds place this 90 was represented by nine in the tens place but either way we're ready to subtract now 11 minus 3 is 8 90 minus 20 is 70 is 70 all right a plus there 500 minus zero is 500 and then nine thousand minus 8,000 is 1,000 and we got the same result because 1,000 plus 500 plus seventy plus eight is 1578