yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Subtracting a 1-digit number with regrouping | 2nd grade | Khan Academy


2m read
·Nov 11, 2024

  • So we have the number 35, which is 3 tens, because we have a 3 in the tens place, so we have 3 tens, and we have a 5 in the ones place. So, this is the ones place, I'll do the ones place in that same purple color. This is the ones place, and we see it represented here as 5, as 5 ones. So 35 is the same thing as 3 tens and 5 ones. 3 tens and 5 ones.

Now, what we wanna do with this video is subtract 8 from 35, and I encourage you to pause the video and try to figure out what 35 minus 8 is. Alright, so let's think about it. We have 5 ones, and we wanna take away 8 ones from there. Well, we don't know how to take 8 ones if we only have 5. We could take away 5, but then we're all out of ones, so how do we take away 8?

Well, this is where regrouping is valuable, because we don't only have 5 squares. We actually have 35 squares. We have 3 groups of ten squares, and then we have the 5 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, if we were to take this group of 10, and 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 1 ten is the same thing as 10 ones, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

So what just happened there? I took away one of the tens, so now I only have 2 tens, and I took those 10 and put them in the ones place. So I have the original 5 ones, and then I have the new 10 that I just took from the tens place. So 5 plus 10 is going to be 15, so I now have 15 ones.

And now I can take away 8. So, if I take away 8 now, I would take away 1, 2, 3, 4, 5, 6, 7, 8, just to be clear. I'm taking away 8. And so what am I going to be left with? Well, I'm gonna be left with 2 tens, I'm gonna be left with 2 tens, and how many ones? I have 1, 2, 3, 4, 5, 6, 7 ones. 7 ones right over here.

Now how do we do it if I didn't wanna draw all of these things? Well, you would've said: Alright, I have 3 tens and 5 ones, this is where we started, but I took one of those tens, I took one of those tens away so I only have 2 tens now, and I took that group of 10 and put it in the ones place, so it's 10 ones.

So the 5 ones, plus another 10 ones, give us 15 ones. 15 ones. And so you can say I have 15 ones minus 8 ones is 7 ones, which we see over here, 1, 2, 3, 4, 5, 6, 7, so after doing the subtraction, we have 7 ones, and then I'll have 2 tens left in the tens place. So 2 tens, 7 ones. 27.

More Articles

View All
The Next Bank To Fail (What Just Happened)
What’s up? Grandma’s guys here, and as it turns out, the entire banking system could be in a lot more trouble than we initially expected. That’s because just days after the collapse of three national banks in a federal reserve bailout, another domino coul…
15 Things That Make Life Worth Living
Nobody can buy a home these days. The rich keep getting richer and the poor poorer. World War Three is buffering on the horizon while the ice caps are melting, and everyone you ask tells you how they just want to get through this week because they’re hold…
Constitutional powers of the president | American civics | US government and civics | Khan Academy
So this is here, um, I’m here with Jeffrey Rosen, head of the National Constitution Center, and we’re going to talk about Article Two of the United States Constitution. So, Jeffrey, what does Article Two deal with? It deals with the executive power, the…
One-sided limits from tables | Limits and continuity | AP Calculus AB | Khan Academy
The function ( f ) is defined over the real numbers. This table gives select values of ( f ). We have our table here; for any of these ( x ) values, it gives the corresponding ( f(x) ). What is a reasonable estimate for the limit of ( f(x) ) as ( x ) appr…
Adding with integer chips | Integers: Addition and subtraction | 7th grade | Khan Academy
Let’s say I wanted to figure out what negative 2 plus negative 4 is equal to. There are a bunch of ways of thinking about them, but what we’re going to do in this video is think about it using something called integer chips. So, with integer chips, if I …
Tailgate Like a Pro: Party Foods That'll Score Big Time! | Chef Wonderful
We’ve got over 50 people coming, a lot of friends and family coming over here, and we want to be ready for the election. [Applause] Oh my goodness! Chef Wonderful here! Can’t believe where I am, Los Angeles, that’s right! And who’s this? Yes, the celebrit…