Project Math Access DVD 02 - Abacus- Part 11
Transcript Start
Audio Description: Part eleven; secrets method; addition; checking work with talking calculator; example one.
TEACHER: Today we're going to talk a little bit and we're, we're just going to kind of show off because this is a review. We're going to do abacus secrets for addition and subtraction. Yeah, sound good? Okay, we're going to start reviewing by turning your abacus the correct way, Joey. Thank you. And I'm going to have you keep it up on the table Thanks.
We're going to start with some direct addition, nice and easy. Now Paras, this is so easy it's so easy, don't make it hard. Don't make it harder than it is, okay? We're going to start out and before we do this we're going to estimate to see if we get an answer that's in the right area. The first problem, so your hands should be on your lap, your head should be towards me and you should have your listening ears on. Thank you. The first problem we're going to do is 45 + 21 Before you set it, let's estimate. 45, let's round that to the nearest 10. What does 45 round to?
JOEY: 40 and 50
TEACHER: It's between 40 and 50 and it rounds up to what, Paras?
PARAS: 50
TEACHER: 50, so we have 50 + 21, what does 21 round to Joe?
JOEY: 20
TEACHER: 20, so we've got 50 + 20 is what Paras?
PARAS: 70
TEACHER: 70, so we know our answer's going to be around what, Joey?
JOEY: 70
TEACHER: I'm going to write your estimate down so we can remember it to check our answer. The problem is 45 + 21. I like how you're not shouting the answer, thank you.
Audio Description: Joey has finished.
TEACHER: What'd you get Paras?
PARAS: 71
TEACHER: Okay, what?
PARAS: 76
TEACHER: Paras got 76, what'd you get Joey?
JOEY: 76
TEACHER: What was our estimate Paras?
PARAS: 70
TEACHER: Okay, is that close?
PARAS: yeah
TEACHER: We'd better check it on the calculator and see. I let you guys do that one on your own. Let's see if we got it right. Let's check the problem Joey. It's 45 + [sound of talking calculator], whoops, better clear that bud.
JOEY: and plus what?
TEACHER: 21 [sound of talking calculator] Let's all clear, 45, remember where the numbers are, let me show you, let me review.
JOEY: I know.
TEACHER: Okay, let's...
CALCULATOR: 45
TEACHER: There you go. 45 +
CALCULATOR: plus
TEACHER: down...
CALCULATOR: 2 1... equal 66
TEACHER: Oh oh, we have a problem don't we? Both of you got what?
JOEY: 60...
TEACHER: Both of you got 76, but the answer is 66. Let's work through this together. Now remember, Joey.
JOEY: I just did it without secrets.
TEACHER: Okay, repeat after me. Stop and listen. Stop and listen. Try. W W-
JOEY: Try, try, try, not cry, cry.
TEACHER: I learn from my mistakes.
JOEY: I learn from my mistakes.
TEACHER: Okay, set 45 for me. Now we want to add 21. Now go to your ones column and add 1. We have 1 direct; you don't need a secret. What'd you get?
STUDENT: 66
TEACHER: There we go, 66. I think what you did is you thought you needed a secret, but did you need a secret for that one?
STUDENT: no