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Edu-Primes
  • 9/18/2024
Transcript
00:00Hello, and welcome to Common Core for Kids Nightly News.
00:09Tonight we have a very special report on someone amazing.
00:15That would be me, of course, the number one.
00:18Let's take a look at the news story that happened to me today.
00:22Hey kids, I have this problem here.
00:26I have this straw and it measured 40 centimeters long, but then I was told to cut it with a
00:31pair of scissors.
00:34So after it got cut, it now only measures 26 centimeters long.
00:40I need to know how much I cut off the straw.
00:45I am stuck since I am not sure how to figure it out.
00:49I do have this number line that I can use to help me get the answer.
00:53Do you guys think I can use the number line to help me find the answer?
00:57Great!
00:59Then let's figure it out together.
01:01Okay, here we have 40, and this is how long the straw measured before it was cut.
01:09Here we see 26, which is how long the straw is after it was cut.
01:15We need to find the length of the piece that was cut off.
01:19So if we counted down the number line from 40 to 26, we should be able to find the length
01:26of the piece that was cut.
01:30We need to count down all these numbers, but that might take a long time.
01:34Let me think of a way to make it go faster.
01:38I know, let's count backwards by 10 so it can go faster.
01:44Let's start at 40 and count back 10.
01:46When we count back 10, we get to 30.
01:50Let's count back 10 again.
01:52Oops, we hit 20.
01:54That's too far back.
01:56So let's go back to 30 and start counting back by 1's.
02:02We start at 30 and start counting back 29, 28, 27, 26.
02:09Great job!
02:10We got to 26.
02:12Now we need to count the jumps that we made.
02:15There's 10, 11, 12, 13, 14.
02:22So the answer is 14 centimeters.
02:25The piece of straw that was cut is 14 centimeters long.
02:29Great job, guys!
02:35Now if we were to look at this problem and write an equation from this, we could solve
02:39it without a number line.
02:41Let's take a look at how to do this.
02:44So we started with the straw that was 40 centimeters long, and we cut off a piece,
02:49but we do not know how much we cut off.
02:51We do know that we were left with the straw that measured 26 centimeters.
02:56You can see here that we have formed an equation by reviewing this problem.
03:00We started with 40, as you see here, and we cut off or subtracted an amount, and we are
03:07left with 26 centimeters.
03:11So we have 40 subtract the unknown number, which equals 26.
03:16Great job so far, but we are not done yet.
03:19One cool thing I have learned is that I can rewrite this to say 40 subtract 26 equals
03:24the unknown number.
03:27If we started with 40 centimeters and took away 26 centimeters, we would get the unknown
03:32number.
03:34So now the problem is easier to see.
03:36Let's work the math.
03:4040 subtract 26, well 0 subtract 6 does not work.
03:45So we regroup by taking a 10 from the 4.
03:49Now we have 10 minus 6, and that equals 4.
03:54Let's move on to the tens place.
03:56We have 3 minus 2, which gives us 1.
04:01We can now see the answer is 14, just like we figured out with the number line.
04:06Now this seemed a little harder, but with practice I know we will get it.
04:11Thanks for learning with me guys.
04:12We will talk to you later.
04:13Goodbye!