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I wish we'd been taught this in high school. One habit I did learn in high school is writing x as two 'c' shapes in a mirror image. This is clearly an x rather

I wish we'd been taught this in high school. One habit I did learn in high school is writing x as two 'c' shapes in a mirror image. This is clearly an x rather than a multiplication symbol. I prefer it to the version listed in the article. I find it hard to distinguish the author's X/χ

samkater 7y ago
Random side-comment - high school is probably the time to do it too. I'm in the middle of teaching my kids how to read/write (the older one) and recognize letters (younger one). I reflexively crossed the "z" when writing out the alphabet the other day and thought to myself, "should I be teaching this?" I decided to erase it and write how they normally see it. I started crossing z's and doing a few of the other tips (some taught, some natural) in this page when it became necessary. But the pedantic in me really wanted to instill it in my kids from the get-go. I suppose experience (going through the problems of mixing up symbols) is the best teacher for the mathematical handwriting solution.
jackpirate 7y ago
X written as )( is the absolute worst. It always looks like two parenthesis when I'm grading student writing and I have no idea how to parse what they write.
- jhanschoo 7y ago
  In high school my teacher preferred that to distinguish it from the multiplication symbol. These days I write it as a times with a hook at the top-left to distinguish (a la most cursive styles, but disjointed), with the added bonus that I write uvwxyz all with the same top-left hook that helps visually group them together, matching their typical role in mathematical writing.
- pbhjpbhj 7y ago
  Do you grade that lack of distinction and teach the student a better orthography? Obviously x is a single symbol that's joined in the middle, so with proper orthography it would seem to be better than using a × as an x? What's your subject?
kaitai 7y ago
at some point in math you'll never use x for times/multiplication -- you'll always use a dot, unless you're specifically doing a cross product. And that is a good stage to reach. (I still have trouble using x for multiplication though.)
- h-cobordism 7y ago
  And the cross product is used with vectors, which are either symbols like u or v, or written with an underscore / arrow on top, so there's zero risk of confusion. (Also, the cross product is always a less elegant alternative to the exterior product, but I guess this isn't the place for that rant.)
- mbeex 7y ago
  > you'll always use a dot No, often you will use nothing - simple juxtaposition.
  - lonelappde 7y ago
    At which point it becomes ambiguous with function application.
  - robocat 7y ago
    Which leads to simple mistakes: http://zerooutoffive.blogspot.com/2008/10/1n-sin-x_21.html http://zerooutoffive.blogspot.com/2008/10/1n-sin-x_21.html
jacobolus 7y ago
> One habit I did learn in high school is writing x as two 'c' shapes in a mirror image. This is clearly an x rather than a multiplication symbol. I prefer it to the version listed in the article. This is an unbelievably ugly handwriting quirk which is sadly prevalent in some European countries. If you do this the ghosts of dead calligraphers will come puke on your paper.
- tester89 7y ago
  Why are people so against it? It literally ressembles x in CMU
gjvnq 7y ago
In my school we always used a middle dot (· U+00B7) for multiplication since 6th grade.
- vitus 7y ago
  That works great until the note that \times returns for cross product, curl, and cartesian product. (And in both cross product and curl, if you substitute a \cdot, then that's an entirely different operation!)

samkater 7y ago

Random side-comment - high school is probably the time to do it too. I'm in the middle of teaching my kids how to read/write (the older one) and recognize letters (younger one). I reflexively crossed the "z" when writing out the alphabet the other day and thought to myself, "should I be teaching this?" I decided to erase it and write how they normally see it. I started crossing z's and doing a few of the other tips (some taught, some natural) in this page when it became necessary. But the pedantic in me really wanted to instill it in my kids from the get-go. I suppose experience (going through the problems of mixing up symbols) is the best teacher for the mathematical handwriting solution.

jackpirate 7y ago

X written as )( is the absolute worst. It always looks like two parenthesis when I'm grading student writing and I have no idea how to parse what they write.

jhanschoo 7y ago
In high school my teacher preferred that to distinguish it from the multiplication symbol. These days I write it as a times with a hook at the top-left to distinguish (a la most cursive styles, but disjointed), with the added bonus that I write uvwxyz all with the same top-left hook that helps visually group them together, matching their typical role in mathematical writing.
pbhjpbhj 7y ago
Do you grade that lack of distinction and teach the student a better orthography? Obviously x is a single symbol that's joined in the middle, so with proper orthography it would seem to be better than using a × as an x? What's your subject?

kaitai 7y ago

at some point in math you'll never use x for times/multiplication -- you'll always use a dot, unless you're specifically doing a cross product. And that is a good stage to reach. (I still have trouble using x for multiplication though.)

h-cobordism 7y ago
And the cross product is used with vectors, which are either symbols like u or v, or written with an underscore / arrow on top, so there's zero risk of confusion. (Also, the cross product is always a less elegant alternative to the exterior product, but I guess this isn't the place for that rant.)
mbeex 7y ago
> you'll always use a dot No, often you will use nothing - simple juxtaposition.
- lonelappde 7y ago
  At which point it becomes ambiguous with function application.
- robocat 7y ago
  Which leads to simple mistakes: http://zerooutoffive.blogspot.com/2008/10/1n-sin-x_21.html http://zerooutoffive.blogspot.com/2008/10/1n-sin-x_21.html

jacobolus 7y ago

> One habit I did learn in high school is writing x as two 'c' shapes in a mirror image. This is clearly an x rather than a multiplication symbol. I prefer it to the version listed in the article. This is an unbelievably ugly handwriting quirk which is sadly prevalent in some European countries. If you do this the ghosts of dead calligraphers will come puke on your paper.

tester89 7y ago
Why are people so against it? It literally ressembles x in CMU

gjvnq 7y ago

In my school we always used a middle dot (· U+00B7) for multiplication since 6th grade.

vitus 7y ago
That works great until the note that \times returns for cross product, curl, and cartesian product. (And in both cross product and curl, if you substitute a \cdot, then that's an entirely different operation!)