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GenX-Education
  • 9/18/2024
Transcript
00:00Hey kids, and welcome back. I have been making doughnuts for my entire school. I have made
00:09a lot of extra doughnuts for me and my dragon, but when I was not paying attention, he ate
00:15some of them. Sorry. When I say some of them, I mean he ate a lot. To find out how many
00:23I have left, I need to subtract three digit numbers. I could use your help. If you are
00:30willing to help me, can you raise your hand? Awesome, thank you so much. Let's get started.
00:40I am having trouble with subtracting when there are zeros in the top number. Here we
00:44have the number 400 subtract 277. I know how to regroup and at first this looks scary,
00:52but once you understand how it works, it is a lot easier. Before we begin, let's bring
00:58in my place value house and show you what 400 looks like. In the number 400, the zeros
01:06mean that there is nothing in that place. In the ones and tens column we have no blocks
01:12since the number in that place is zero. In the hundreds column we have four or four hundreds.
01:19You can see the hundreds blocks and there are four of them. Now looking back at the
01:25problem, we need to start subtracting in the ones place first. We cannot do this because
01:30we cannot take 7 away from zero. We need to regroup or borrow from the tens place to be
01:36able to subtract. What number is in the tens place? Zero, right, so let's borrow from the
01:42zero. Wait a minute, we can't do that, we cannot borrow from a zero. Where should we
01:49borrow from next? The hundreds place, great job. So we cross out the four and put a three
01:57there since we are borrowing one of the hundreds. Now here is the tricky part, we cannot take
02:03this hundreds straight to the ones place, we have to go down the line. So we put a ten
02:08in the tens place. Now we can see that we have three hundreds in the hundreds place,
02:15ten tens in the tens place, and zero ones in the ones place. We still need to borrow
02:21to be able to subtract in the ones place, but now that the tens place has a ten in it,
02:26we can borrow from that. So we take one of the tens and bring it to the ones place and
02:33that leaves nine tens in the tens place. Awesome job, we took one of the tens from
02:39the tens place and now have ten ones to subtract with. Great job guys. Now we have ten subtract
02:47seven which gives us three. Onto the tens place we have nine subtract seven which gives
02:54us two. In the hundreds place we have three subtract two which gives us one. The answer
03:03is one hundred twenty three. That was so cool, awesome job. It is a lot easier to work these
03:11problems when we remember place value. We regroup or borrow from the next digit until
03:16we can subtract. Let's try one more without using the blocks. Ok, I baked five hundred
03:26donuts for my school and my dragon ate one hundred ninety five donuts. That was a lot
03:32of donuts. Here we have the problem five hundred subtract one hundred ninety five. Just like
03:38before we start with the ones place. We cannot take five away from zero so we need to borrow
03:44from the tens place. In the tens place we have zero so we cannot borrow from the tens
03:50place either. We now look at the hundreds place. There is a five in the hundreds place
03:57so we borrow one from it which leaves four in the hundreds place. We put a ten in the
04:03tens place to show the hundred that we borrowed. You do not stop there since we need to get
04:08to the ones place. We now can borrow from the tens place since there is a ten there.
04:13So we borrow one of the tens and that leaves nine in the tens place. Now we have a ten
04:22in the ones place and we can start subtracting. Ten subtract five is five. In the tens place
04:30we have nine subtract nine which is zero. The hundreds place has four subtract one which
04:39gives us three. The answer is three hundred and five. I have three hundred and five donuts
04:47left for my school. Thanks for your help. I better get baking since I need a lot more
04:54donuts for my school. Goodbye.