Cross multiplication — symbol?
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January 8, 2021 at 1:12 am #36535JhqbrailleParticipant
This question came up on a braille board today.
A "symbol" for cross multiplying is used on a worksheet. It looks like a northeast arrow crossed with a northwest arrow, but it is used like an mathematical operation for cross multiplying. Attaching the print, voiced problem: fraction 1 over 4a end fraction (cross multiply symbol) fraction 9 over 2 end fraction.
The symbol isn't on a list, but then again, it isn't on a mathematical list at all. It's a madeup symbol. So, should it be a transcriber defined symbol or a graphic, or is there really a symbol in braille that corresponds to this one. Incidentally, there are other similar symbols that represent cross multiplication with arrows down or other directional difference. So, if doing a transcriber defined symbol, there would likely be more than one.
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You must be logged in to view attached files.January 11, 2021 at 1:15 pm #36543kdejuteModeratorThank you for the question!
You're right that the symbol you are asking about is not given a braille symbol in the UEB Guidelines for Technical Material.
Possibly an intuitive transcriberdefined shape symbol (e.g., @$cross) could work for this crossmultiplication symbol. If it appears frequently, assigning one of the transcriberdefined symbols may be advisable. [Our brief webinar "UEB Technical  Underlying Rules and Print Symbols," at time 12:40, touches on transcriberdefined shapes and symbols.]
Regardless of whether you use a transcriberdefined shape (GTM 14.2) or transcriberdefined symbol (GTM 11.2), your description of the print sign is an excellent starting point. (Considering the other uses of this sign, would it be appropriate to include in its description the equals sign which appears to be printed "underneath" the crossmultiply sign we're discussing?) In a perfect world, we would even provide the student with a tactile graphic representation of the crossed arrows (in addition to an excellent description).
–Kyle
January 14, 2021 at 7:44 am #36576JhqbrailleParticipantKyle:
Thank you so very much! This is what I wrote to the transcriber prior to posting the question on the board:
As far as I can see, the perceived "cross multiplying symbol" is a graphic. If you put an equals sign and instruct students to cross multiply, as long as they have had instruction in this method, they know what to do. If you see this a lot, I would use a transcriber defined symbol. Could get tricky, though, cause those arrows change direction.
My first thought was to use graphic tape with the description underneath an equals signand that was before you told me the equals sign was there! I didn't see it at all!
But, both expediency and logic held me back from saying that. If there are a lot of those, that could get old fast. It would also change the linear math to spatial math. Spatial display is a lot for a student to go through to get to the math and keep up in class. But, if it were a teaching method that is being demonstrated just a few times, I'd definitely go for a graphic. Welcome to my idealistic perfect world where we have all the time we need!
Love the idea of the transcriber defined (shape sign "cross"), but I noticed in my research that these cross multiplying symbols change directions. There are also cross multiplying down arrows and side arrows, etc., so I was wondering if I could incorporate the two directional arrows somehow.
A transcriber defined symbol... What about something like this: ⠆⠳⠜⠻⠳⠣ . It's on the line with something I found in the Technical Update manual at CNIB ⇄ with two arrows going opposite horizontal directions, in the same "combined" symbol, transcribed like this: ⠆⠳⠕⠻⠳⠪ . This way the symbol could be changed easily if the directions of the arrows changed.
⠨⠿⠳⠎ ↗ simple up and right pointing arrow (northeast)
⠨⠿⠳⠣ ↘ simple down and right pointing arrow (southeast)
⠨⠿⠳⠱ ↖ simple up and left pointing arrow (northwest)
⠨⠿⠳⠜ ↙ simple down and left pointing arrow (southwest)What do you think? Oh, and let me know if the braille showed up in the body of the question. New toy at Branah.com. Had to trick it to come up with the braille thoughit didn't work with ascii.
Jill

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