Project Math Access DVD 02 - Abacus- Part 07
Transcript Start
Audio Description: Part seven; basic computation: braillewriter, abacus and calculator; example three.
TEACHER: What I'm going to do is put a pile over to the right, okay? And as you put 6 into the hundreds column, then you can go to your tens column and puts, okay? But let‘s see what we've got in out hundreds column right now.
Audio Description: There are five cubes in the hundreds column. Ali starts to count them, but loses track.
TEACHER: You know what I would do to help you get organized. I would push them all to the top and then as you count them, bring them down. So you know which ones you've counted, okay?
Audio Description: The teacher an Ali move the cubes to the top of the slot. Ali moves the cubes to the bottom as she counts them.
ALI: Okay. 1, 2, 3, 4, 5
TEACHER: Okay. Do we need another one?
ALI: Yep
TEACHER: Come over to your pile on the right.
Audio Description: Ali adds a cube to the hundreds slot.
ALI: 6
TEACHER: Okay. Do you remember what the number was?
ALI: No
TEACHER: Oh, you‘d better write it down, huh? Yeah, let‘s write it down. It was 685. Don't forget to drop your numbers, please.
ALI: No dollar sign, right?
TEACHER: Not right now, nope
ALI: 65
TEACHER: Alright.
Audio Description: Ali searches for eight cubes to put in the tens slot. She transfer's cubes from the ones slot to the tens slot.
ALI: six,... eighty... oh my gosh
TEACHER: Oh, this is so much work, I know.
ALI: eighty...
Audio Description: She has eight cubes in the tens slot. She reaches into the bin for more cubes. Ali has five cubes in the ones slot.
ALI: Whoa, I've got just enough cubes.
TEACHER: Look at that. Now I've got to double check your work, just to make sure we don't have any uninvited guests at the party, okay?
Audio Description: Ali counts cubes in the ones slot as the teacher checks her work.
ALI: (quiet counting) at the 685th party.
TEACHER: At the 685th party, 1, 2, 3, 4, 5, 6, 7, 8...
Okay, we don't have any uninvited guests this time. That's good.
ALI: Oh my gosh.
TEACHER: Okay. Let's estimate first. 685, that's between two hundreds. What two hundreds it that between?
ALI: 600 and 700
TEACHER: Okay. Would it round to 600 or 700, do you think?
ALI: 700
TEACHER: Alright. Now I want you to round it to the nearest ten for me. Now remember, let me give you a little hint first, okay? If it's 5 or higher you round...
ALI: up
TEACHER: If it's 4 or lower, you round...
ALI: down
TEACHER: Okay, 685, round that to the nearest ten please.
ALI: 90
TEACHER: Oh, except you forgot the 600.
ALI: 690
TEACHER: Okay. I could see your wheels turning in your brain. Okay, you've got a secret 5. We're going to push that up so we don't forget our secret 5, okay? So our estimate it 690. You hand the cashier 7 dollars and write it down because you want to make sure you get back all your money. Excuse me, you want to make sure you get back all your money. We don't want to get short-changed, okay?
ALI: No dollar sign, right?
TEACHER: No, not right now.
TEACHER: Okay, speedy on the braillewriter. Okay. Hello, maam. Your total comes to 6.85. Give me the money, please.
ALI: six eighty-five
TEACHER: How much money are you handing me?
ALI: six eighty-five
TEACHER: No, you're handing me 7 dollars.
ALI: Oh. 1, 2, 3,4, 5, 6, 7
TEACHER: Okay, now let's count up. This is kind of easy to count up. We rounded to 690, we gave the cashier 7 dollars, how much change would you get back?
ALI: 10
TEACHER: Don't forget your secret 5.
ALI: 5
TEACHER: 10 plus the secret 5
ALI: Oh plus
TEACHER: Aha, what are you going to get?
ALI: 15
TEACHER: You'll get 15 cents back, okay. Now I want you to write this subtraction problem, and we're just going to space over and write it horizontally. Hallelujah, no vertical, okay? Now what is the subtraction problem?
ALI: 685 minus 700
TEACHER: Whoop, stop and think about that.
ALI: 700 minus 685
TEACHER: There we go. There we go. Okay.
ALI: We don't need the dollar sign, do we?
TEACHER: We're just going to talk about it as hundreds right now.
ALI: [sound of braillewriter] minus 685
TEACHER: Don't forget your equals please. Okay, now comes the point where we check it on the...
ALI: Abacus
TEACHER: umhum
Audio Description: Ali turns to her abacus.
ALI: 600...
TEACHER: Oh, what is our subtraction problem? We're getting careless here. We're speedy Gonzalez, slow down, no race, slow down.
ALI: 700
TEACHER: Make sure you're in the right column.
ALI: 700
TEACHER: Okay, now this is where I want chatty Barbie. Talk it out.
ALI: This is going to be hard.
TEACHER: Alright. I think you can do it. I have faith in you.
ALI: minus 685
TEACHER: Okay
ALI: Subtract the 500, add 100
TEACHER: Ah, slow down there. Look at your problem again. We've got 7 dollars, what are we subtracting from it?
Audio Description: Ali checks the problem in the braillewriter.
ALI: 685
TEACHER: Okay. What do we subtract from that tens column?
ALI: ten?
TEACHER: I'm sorry, from the hundreds column?
ALI: 500
TEACHER: No.
ALI: 100
TEACHER: Look carefully here. What's our problem? We've got 7 dollars minus...
ALI: 685
TEACHER: Yes, 6, we subtract a 6. Did you subtract your 6?
ALI: Yeah.
TEACHER: Okay. And what do we subtract from the next column?
ALI: 80
TEACHER: Okay. Do we have it?
ALI: No.
TEACHER: Alright, let's hear you talking. Is 50 available?
ALI: No, we don't have a 50 or 60, 70, 80.
TEACHER: We don't have anything, so what do we do?
ALI: So we minus a hundred...
TEACHER: Okay and set what?
ALI: 20
TEACHER: Okay, because 100 minus 20 is...?
ALI: 80
TEACHER: Right. And what do we need to subtract from our ones column?
Audio Description: Ali, again, refers to the problem in the braillewriter.
ALI: 5
TEACHER: Right, so subtract the 5. Uh-oh!
ALI: We don't have 5.
TEACHER: We don't have 5. 5 is unavailable at the moment.
ALI: This is easy.
TEACHER: Alright, it's easy.
ALI: Add 10.
TEACHER: Ah, ah, ah, we're not adding, we're subtracting. So we subtract what?
ALI: 10
TEACHER: Alright, but that's too much.
ALI: Add 5.
TEACHER: Alright, what'd you get?
Audio Description: Ali refers to the abacus.
ALI: 1 dollar, no,... one-hundred and five
TEACHER: Look carefully. What columns are those in?
ALI: 15
TEACHER: 15. Write your answer down for me please. And then we are going to check it on the calculator.
TEACHER: Okay. Check it for me.
Audio Description: Ali finds the calculator.
TEACHER: Just to double-triple check.
Audio Description: Ali, refers the problem in the braillewriter.
TEACHER: Good thing we wrote it down.
ALI: 700
CALUCLATOR: seven zero zero
ALI: are we doing dollars now?
TEACHER: No, since you forgot to put the decimal point in just subtract...
ALI: Because it will be the same thing.
TEACHER: Yeah. You're on the right track, except when you have dollars, where does that decimal point go?
ALI: Between the dollars and the hundreds
TEACHER: Between what?
ALI: the hundreds and the thousands
TEACHER: If you had 700 and you wanted to put it in as a dollar, how would you put it in?
ALI: seven point zero zero
TEACHER: Thank you. I knew you knew what you were talking about.
CALCULATOR: six eight five equals one five
TEACHER: Did you get it?
ALI: Yep
TEACHER: Alright, give me five. Alright now, we're going to stop with the problems, but just to kind of wrap up everything, we're going to do a few more things. Okay?
ALI: Yep
TEACHER: Alright. Let's talk about, if we had 685 in dollars, how could you make that? Tell me how you would make that.
ALI: 6 dollars and 85 cents
TEACHER: Yes. How would you make that? Tell me with dollars and coins.
ALI: Maybe 6 dollars
TEACHER: Okay.
ALI: 6 dollar bills
TEACHER: 6 dollar bills, okay.
ALI: No, a 5 dollar bill and a1 dollar bill
TEACHER: Oh, okay, you're getting creative, okay. A 5 dollar bill and a1 dollar bill, okay.
ALI: and then 2 quarters
TEACHER: Okay.
ALI: and 3 dimes
TEACHER: Okay.
ALI: and a nickel
TEACHER: Oh, good job. Give me five.