Addition with carrying
Addition 3 Practice carrying digits to add multiple digit numbers
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- What I want to do in this video is one, just do a bunch of
- addition examples so that we really get some good practice
- and we really get warmed up with addition.
- And what I even more want to show you is that we now have
- all the tools we need to really tackle any addition problem.
- So let's just get warmed up with some one-digit addition
- problems, but these are the ones that always give me a
- little bit of a headache.
- Let's start with a really, relatively straightforward one.
- I want to say two plus four.
- Well, we know what that is.
- I don't think we need to draw the number line at this
- point, but you can if you need to remember this.
- Two plus four is six.
- Not too bad.
- What about nine plus three?
- We saw that in the last video.
- Nine plus one is ten.
- Plus another one is eleven.
- Plus three is twelve.
- Nine plus three is twelve.
- And it's probably not a bad idea.
- It's good to visualize what's happening here, but it's also
- not a bad idea to be able to do these very fast.
- To be able to memorize, at least what the one-digit
- addition problems end up being.
- Let's do a couple of harder ones.
- Six plus seven.
- This one I used to find difficult to remember.
- But six plus seven is thirteen.
- Draw out the number lines and the lemons and limes
- if you don't believe me.
- Six plus seven is thirteen.
- Eight plus six or six plus eight is going to be fourteen.
- And that's the same thing as seven plus seven -- is
- also going to be fourteen.
- And if you think about it, we got the same
- number here as there.
- And it makes sense, right?
- Because we took one away from eight, but we had one more than six.
- So it's like you just shifted the one from the eight to the six.
- That's why we got the same answer.
- If that confused you, ignore it.
- Let's just do a couple of more of these.
- So eight plus eight is sixteen.
- These are things that hopefully you'll be able to do super fast
- in the not too far off future.
- Five plus six.
- Well, that's eleven.
- Let me just do a couple of more really fast.
- So let's say seven plus nine is going to be sxiteen.
- You might want to draw the number line if
- you don't believe me.
- And that's going to be the same thing as eight plus eight, is also sixteen.
- And then nine plus nine is eighteen.
- And then nine plus eight is seventeen.
- And that's just a little bit of warm up.
- We didn't do all of the possible combinations of
- one-digit numbers, but these are some of the ones that
- give people a little bit more headache.
- So now that we've done that let's tackle some larger digit
- numbers that we started doing in the previous video.
- Maybe I'll leave that there for now.
- So let's do a couple of them.
- Let's do twenty-two plus three.
- So we go to the ones place.
- Two plus three is five.
- We didn't have to carry anything.
- And then in the tens place we just have this two sitting here.
- So we just take that two.
- Two plus nothing -- it's two tens.
- It's two dimes.
- So then we put that down there.
- So we get twenty-five.
- Two dimes and five pennies, or twenty-five cents depending -- a lot of people,
- money makes it easier to understand things or maybe
- to be motivated to understand things.
- All right, let's do another one.
- What is thirty-eight plus seventeen?
- So we look at just the ones place.
- What is eight plus seven?
- We haven't done that one yet; I'll do it up here.
- Eight plus seven is equal to-- it's going to be one
- more than eight plus six.
- Eight plus six is fourteen, then eight plus seven is going to be
- one more than that.
- So it's going to be equal to fifteen.
- So in this problem we write the five here.
- Let me write this in a different color.
- So the five in the fifteen we'd write right down there
- in the ones place.
- And we would carry the one because that's one dime.
- That's one ten.
- You know, this fifteen, this is ten plus five.
- So this one really means one ten or one dime.
- So we put that one up there in the tens place.
- We have one plus three is four.
- Plus one is five.
- So you get fifty-five.
- One plus three plus one is this five.
- Thirty-eight plus seventeen is fifty-five.
- Or five tens and five ones.
- That's the same thing as fifty-five.
- Let's do a couple more problems.
- I think you'll see that we have the tools to tackle
- anything, any problem.
- Let's say we have forty-seven.
- Let me switch colors just so it stays interesting.
- Forty-seven plus nine.
- We just look at the ones place.
- Seven plus nine.
- We know what that is already.
- We did that problem already.
- Seven plus nine is sixteen.
- So you write the six in the ones place and carry the one.
- And now it's in the tens place.
- Because this is one ten right there.
- So one dime plus four dimes is five dimes.
- So it's five dimes and six pennies.
- It's fifty-six.
- Let's do slightly harder problems.
- Let me scroll down a little bit so we have some
- space to work with.
- We always need that.
- All right, let's do something hard.
- Ninety-nine plus eighty-eight.
- That's a hard one.
- And you just have to look at the parts of the problem and
- you'll see how it'll all work out.
- You say, what's nine plus eight?
- We did that up here.
- Nine plus eight we know already is seventeen.
- That's a good one to remember.
- Nine plus eight is seventeen, but it's always good to be able
- to visualize it as well.
- So nine plus eight is seventeen.
- Carry the one.
- And then we have one plus nine is ten.
- Ten plus eight is eighteen.
- Now this is interesting.
- We want to write eighteen down.
- So we write our eight down there.
- We have one plus nine plus eight.
- One plus nine plus eight is equal to eighteen.
- We wrote the eight down there and we say, let's carry the one.
- We carry the one, but we carry it into the hundreds place.
- This was the ones place, the tens place, now we're
- in the hundreds place.
- But there's nothing else in the hundreds place.
- So it just drops straight down.
- So you could almost just write the eighteen just like that.
- So ninety-nine plus eighty-eight is one hundred and eighty-seven.
- Let's keep doing some examples.
- You could see, it's all the same pattern.
- We could add two ten-digit numbers to each other as
- long as we're just careful about carrying our digits.
- So let's do seven hundred -- let me switch colors.
- Well do some three-digit numbers.
- Let's do a four-digit number.
- Let's not mess around.
- Let's do a four-digit number.
- So let's do four thousand, three hundred and sixty-eight plus five hundred and seventy two.
- Let's see what happens here.
- I'll write it down here.
- Eight plus two.
- We know that that is equal to ten.
- You can do the number line if you need to.
- Eight plus two is equal to ten.
- Put the zero in the ones place, carry the one.
- Now we're in the tens place.
- This is really one ten.
- This is six tens.
- This is seven tens.
- Or you could think of them as dimes if we're
- thinking about change.
- So one dime plus six dimes is seven dimes.
- Seven dimes plus seven dimes is fourteen.
- Let me write it like this.
- We could write one plus six plus seven is equal to -- one plus six is seven.
- Seven plus seven is fourteen.
- So this right here is going to be equal to fourteen.
- Carry the one.
- Now we have-- let me do it in another color.
- I'll do it in pink.
- We have one plus three.
- We're in the hundreds place now.
- Plus five.
- One plus three plus five.
- Well, one plus three is four.
- Plus five is nine.
- Four plus five is nine, so this is going to be equal to nine.
- Nothing to carry.
- We only had something in our ones place.
- Nine is just nine pennies.
- It's no dimes.
- It's just nine pennies.
- And then we go to the thousands place.
- Nothing to add to the thousands place.
- So you just take this four thousand -- you see a four here, but since
- it's in the fourth digit to the left, this means four thousand.
- So this four thousand right here, we don't have any other thousands
- to add it to, so we just bring it straight down.
- So you bring the four down there.
- So four thousand, three hundred and sixty-eight plus five hundred and seventy-two is four thousand -- we'll put a comma there
- to make it easy to read --
- four thousand, nine hundred and forty.
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At 5:31, how is the moon large enough to block the sun? Isn't the sun way larger?
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