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This thing called new math??

(30 Posts)
WaywardOn3 Sat 06-Dec-14 12:38:23

https://m.youtube.com/watch?v=UIKGV2cTgqA

:-o I don't think we did it like this when I was at school, base 10 yeah but base 8? It sounds so complicated

Unitedwestand Sat 06-Dec-14 12:43:28

The answer is 59 not 69

ilovepowerhoop Sat 06-Dec-14 12:45:59

there should be a 1 added onto the 7 to make it 8 so that it becomes 13-8 to give 5

The above method (when done correctly!) was the way I was taught many years ago (I am 41)

kim147 Sat 06-Dec-14 12:49:35

Message withdrawn at poster's request.

wowfudge Sat 06-Dec-14 12:51:15

What? ilove what you have suggested is wrong to me. The 13 on the top row should be 12 as ten has been borrowed from that number to enable 3 to be deducted from 12 on the far right. When you work to the left, you will have 1 minus 1, thus cancelling each other out.

kim147 Sat 06-Dec-14 12:52:59

Message withdrawn at poster's request.

sashh Sat 06-Dec-14 12:53:44

nothing wrong with base 8 or 16 or 2 - but then I#ve been programing for 35 years, and we did this at school

ilovepowerhoop Sat 06-Dec-14 12:54:31

www.mathsteacher.com.au/year7/ch01_whole/03_sub/sub.htm - explains the 2 methods. I was taught the equal additions method and dh was taught the decomposition method.

my dc's are getting taught the decomposition method

DoJo Sat 06-Dec-14 12:56:24

Don't let the screen shot from the video distract you - the original sum is 342-173, so what you are seeing in that single frame is the half way point of the calculation!

ilovepowerhoop Sat 06-Dec-14 12:57:18

wowfudge they are using a different method where you add 10 to the top and 10 to the bottom in the next column on the left. There are different subtraction methods to get the same answer

ilovepowerhoop Sat 06-Dec-14 13:02:58

should show the 2 methods

ilovepowerhoop Sat 06-Dec-14 13:03:33

you need to click the blurry bit to see the proper picture

eddiemairswife Sat 06-Dec-14 13:11:16

I learnt that way ilove. I'm a fair bit older than you, and we were told "borrow from the top, pay back at the bottom". Still do subtraction like that in spite of many years teaching the other method.

noblegiraffe Sat 06-Dec-14 13:11:22

The Tom Lehrer song in the OP is a bit of a piss take. Also new math is old math now and not a UK thing.

ilovepowerhoop Sat 06-Dec-14 13:11:53

342
-173

3 ¹4 ¹2
-¹1 ¹7 3
-----
2 6 9

ghostyslovesheep Sat 06-Dec-14 13:16:29

yes I'm 44 and we did decomp - and yes the answer is 59 grin

kim147 Sat 06-Dec-14 13:20:39

Message withdrawn at poster's request.

ilovepowerhoop Sat 06-Dec-14 14:07:13

sorry my answer above should be 169

bloodyteenagers Sat 06-Dec-14 14:33:31

'New Math' is something that was introduced briefly back in the 60's. The youtube thing was a satirical song written by Tom Lehrer.
Had great fun before the summer holidays, winding up a teacher with this because of the changes that where coming to the curriculum grin

SecretSquirrels Sat 06-Dec-14 14:38:02

I did it at school in the late 1960s. I didn't realise that it was a flash in the pan, wondered why DC didn't do it. I was never any good at Maths in general but did quite well in the bases topic. IIRC we had to work base 8, base 12, and base 2 ie binary.

ilovepowerhoop Sat 06-Dec-14 15:30:54

I was taught it in the 70s/early 80s in Scotland

Bilberry Sun 07-Dec-14 20:40:19

In base 8 isn't the answer to the sum in the first post 37? Surely you can't have a 9 in base 8?

OmnipotentQueenOfTheUniverse Sun 07-Dec-14 20:47:13

Ha bilberry that was what I was going to post! that you can't have a 9 in base 8.

I haven't worked out what it should be though as I don't have a pencil to hand grin

OmnipotentQueenOfTheUniverse Sun 07-Dec-14 20:49:15

yeah I get 37 too

OmnipotentQueenOfTheUniverse Sun 07-Dec-14 20:49:50

went and got a pencil after all grin

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