# Foo - Left to Right addition SUCKS!

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View Full Version : Left to Right addition SUCKS!

RubenX
03-01-10, 08:50 PM
Who the heck came up with this idea? And how the heck are parents supposed to help their children with math homework if they are now told to add in this totally weird alien way? SUCKS SUCKS SUCKS!

And that's it

StupidlyBrave
03-01-10, 08:56 PM
Aliens have really fast spaceships. So don't knock it until you've tried it :thumb:

Seriously though. This is just arithmetic, right? It's the same either way.

RubenX
03-01-10, 09:03 PM
Aliens have really fast spaceships. So don't knock it until you've tried it :thumb:

Seriously though. This is just arithmetic, right? It's the same either way.

see back in the 70's where it was simple:

19
+11
-----

We use to start on the right, adding 9 +1 which gave us 10... place the 0 down there, get the 1 on top of the next column, then add the three 1's which is 3 and put the the 3 down there .... voila! = 30

But the other way around, 1 + 1 = 2, then you move to 9 + 1 = 10 and that makes my boy end up with fricking 210 as a result. *me nods*

And because I have no idea what the heck he's thinking, I'm having a lot of trouble pinpointing where he's getting it wrong. Google pointed me to this (http://searchwarp.com/swa51677.htm)... arg.. this sucks

PS: oh, and my girl ate ALL my fricking cookies... all of them! didn't left a single one for me :mad:

Tom Stormcrowe
03-01-10, 09:11 PM
It's like using a slide rule is all (Kinda).

StupidlyBrave
03-01-10, 09:19 PM
Kids today don't have the benefit of lead in their paint chips like we did back then.

We learned that way through endless repetition. I assume that your son's addition section was immediately preceded by problems involving estimation. I also assume he'll have a lot more of these.

The point is, that he is supposed to recognize the significance of the place value (i.e. it's ten not one). That is precisely the advantage that the link you provided cites. It's probably better to stick to one methodology than confuse him by introducing another.

BTW, I learned to read in ita. Look where that went :rolleyes:.

<3 2 Ride
03-01-10, 09:21 PM

see back in the 70's where it was simple:

19
+11
-----

We use to start on the right, adding 9 +1 which gave us 10... place the 0 down there, get the 1 on top of the next column, then add the three 1's which is 3 and put the the 3 down there .... voila! = 30

But the other way around, 1 + 1 = 2, then you move to 9 + 1 = 10 and that makes my boy end up with fricking 210 as a result. *me nods*

And because I have no idea what the heck he's thinking, I'm having a lot of trouble pinpointing where he's getting it wrong. Google pointed me to this (http://searchwarp.com/swa51677.htm)... arg.. this sucks

PS: oh, and my girl ate ALL my fricking cookies... all of them! didn't left a single one for me :mad:

The error is in saying that 1 + 1 is 2. You are breaking apart the numbers into tens and ones and combining. It is really adding 10 + 10 and 9 +1 and combining those two sums. So 10 + 10 is 20 and 9 +1 is 10, now add 20 and 10 together to get a sum of 30. This method is meant to preserve place value in addition.

GP
03-01-10, 09:25 PM
The error is in saying that 1 + 1 is 2. You are breaking apart the numbers into tens and ones and combining. It is really adding 10 + 10 and 9 +1 and combining those two sums. So 10 + 10 is 20 and 9 +1 is 10, now add 20 and 10 together to get a sum of 30. This method is meant to preserve place value in addition.
1+1 doesn't equal 2? No wonder it took me 4 years to get to second grade.

RubenX
03-01-10, 09:29 PM
The error is in saying that 1 + 1 is 2. You are breaking apart the numbers into tens and ones and combining. It is really adding 10 + 10 and 9 +1 and combining those two sums. So 10 + 10 is 20 and 9 +1 is 10, now add 20 and 10 together to get a sum of 30. This method is meant to preserve place value in addition.

You are a teacher aren't you?

<3 2 Ride
03-01-10, 09:29 PM
1+1 doesn't equal 2? No wonder it took me 4 years to get to second grade.

Man I love Foo. :lol:

1 + 1 = 2 when you are talking about numbers with a place value of one. However, when you are talking about numbers with a place value of ten, 1 + 1 is really 10 +10. I would guess that place value is why it took you 4 years to get to second grade. :p

UnsafeAlpine
03-01-10, 09:30 PM
You are a teacher aren't you?
She's the hot teacher... :innocent:

SingingSabre
03-01-10, 09:37 PM
She's the hot teacher... :innocent:

Oh woah woah, I'm hot for teacher!

JoelS
03-01-10, 09:41 PM
1+1=10 in binary

RubenX
03-01-10, 09:47 PM
1+1=10 in binary

Great... now I also need to teach the boy about transistors, logic gates, flip flops, carnaugh maps, circuit states, 8-bit assembly.....

Connell
03-01-10, 09:52 PM
Calvin explains it all here.

http://www.grymonpre.com/math/chmath.htm

RubenX
03-01-10, 10:01 PM
Calvin explains it all here.

http://www.grymonpre.com/math/chmath.htm

lol... that's win

http://www.grymonpre.com/math/chmath_files/image008.jpg

skiahh
03-01-10, 10:18 PM
Who the heck came up with this idea? And how the heck are parents supposed to help their children with math homework if they are now told to add in this totally weird alien way? SUCKS SUCKS SUCKS!

And that's it

Just rearrange it to do the calculations... what's the big deal how it's presented on paper?

4+6+5+3+2+7=? is no different than:

4
6
5
3
2
+7
------
?

Can you not do the transposition, then take the answer and put it on the right side of the left to right equation??

Allen
03-01-10, 10:28 PM
Just rearrange it to do the calculations... what's the big deal how it's presented on paper?

4+6+5+3+2+7=? is no different than:

4
6
5
3
2
+7
------
?

Can you not do the transposition, then take the answer and put it on the right side of the left to right equation??

Adding a line of single digits, yeah, but the some of 465 + 327 = ? is easier to visualize as 465
.................................................................................................... ................................+ 327
.................................................................................................... .................................-------

CliftonGK1
03-02-10, 12:14 AM
The "new math" is all well and good until the kids hit college, and professors expect everyone to understand and utilize the "old school" methodology.

ModoVincere
03-02-10, 06:12 AM
1+1=10 in binary

Tom Stormcrowe
03-02-10, 06:29 AM

MSsxPTI=

(Base 64 for 1+1=2)

ModoVincere
03-02-10, 06:35 AM
MSsxPTI=

(Base 64 for 1+1=2)

I is wussy then, cause that reads like greek.

Tom Stormcrowe
03-02-10, 06:46 AM
think MIMEencoding
I is wussy then, cause that reads like greek.

Metzinger
03-02-10, 06:49 AM
I was taught short division in grade 4.
Got called on it in junior high by a marker who wanted to see my work.
Then I had to get up in front of the whole class and demonstrate it on the blackboard. People were looking at me like I was an alien.
I still wake up screaming.

RubenX
03-02-10, 08:00 AM
Gee, I don't even remember what the heck I was doing in 4th grade. I only remember the school I went to and the girl I liked.

apricissimus
03-02-10, 08:06 AM
I think it's a good idea to teach several different ways to add. Or multiply, or whatever.

In my head I add 19 and 11 like this: Take 1 from 11 and add it to 19 to get 20. Since you took the 1 from 11, it's 10 now. So add 10 to 20 to get 30.

Emphasizing just one method makes it seem like a recipe, or just a typographical trick. Introducing different methods increases the chances that one of them will click with a student, and they'll see what's really going on. And teaching different methods encourages kids to use different mental models to do mathematics, a very useful skill.

jsharr
03-02-10, 09:01 AM
Adding a line of single digits, yeah, but the some of 465 + 327 = ? is easier to visualize as 465
.................................................................................................... ................................+ 327
.................................................................................................... .................................-------

My sons' school has parent math night each year, where the teaching staff for that grade level shows the parents the way they want the kids to learn math. We are doing this linear math. 465 + 327 you would take the 100s first, the the tens, then the ones and get

400 + 300 = 700 then 60 +20 = 80 then 5 +7 =12 then 700 + 80 = 780 then 780 + 12 = 790. My son can do this sort of stuff in his head now at age 7. I think it gives them more problem solving skills. Some kids have trouble conceptualizing the "carrying" of the remainder.

They show the kids three or four ways to reach the same end result, that way the child can decide which works best for him. Not sure there is any right way, or better said, that any one method is more right than another.

Siu Blue Wind
03-02-10, 09:23 AM
Never saw that way to add. Seems a heck of a lot easier.

coasting
03-02-10, 09:26 AM

no shame. better hope your kids don't realise.

Actually, that brings up an interesting thought. how old will they be when they realise daddy is not superman.

dstrong
03-02-10, 09:33 AM
Got called on it in junior high by a marker who wanted to see my work.

I'm assuming that "marker" = "teacher"?

gremlin76
03-02-10, 08:37 PM
465 + 327... 400 + 300 = 700 then 60 +20 = 80 then 5 +7 =12 then 700 + 80 = 780 then 780 + 12 = 790.

weird, i came up 792, the old fashioned way. i put 465 over 327 and added down, took me about 1.4 seconds on paper. and i got the correct answer!

jsharr
03-03-10, 08:31 AM
weird, i came up 792, the old fashioned way. i put 465 over 327 and added down, took me about 1.4 seconds on paper. and i got the correct answer!

you obviously are a scholar and not a texican cretin. I cannot chew gum and walk at the the same time, how do you expect me to form semi cohesive sentences and do math at the same time? Also, what is the best way to get egg off of one's face, oh great and all knowing Gremlin76?:thumb::D

mikeybikes
03-04-10, 01:56 PM
Where's the kid's calculator?

chevy42083
03-04-10, 02:16 PM
Just rearrange it to do the calculations... what's the big deal how it's presented on paper?

4+6+5+3+2+7=? is no different than:

4
6
5
3
2
+7
------
?

Can you not do the transposition, then take the answer and put it on the right side of the left to right equation??

That's what we were taught to do. Math was given in one line (to save space), but we were never expected to work it like that.