Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

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## #1 2009-01-25 03:49:08

JaneFairfax
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### Multiplication symbols

There are three common ways to represent the arithmetic operation of multiplication:

(i) by the cross symbol × (often called “times”):

(ii) by a dot:

(iii) by nothing:

The last method is not suitable for raw numerals 0, 1, 2 etc –
is generally interpreted as the single number “twenty-three” rather than the operation “two times three”. The best multiplication symbol to use for numerals is the cross symbol.

If you use a dot with numerals to represent multiplication, make sure you use a centre dot rather than a baseline dot. In LaTeX, it should be formatted with the \cdot command. Do not use the baseline dot for multiplication – that represents a decimal point!!

Last edited by JaneFairfax (2009-01-26 01:06:51)

Q: Who wrote the novels Mrs Dalloway and To the Lighthouse?

## #2 2009-01-25 16:00:57

ganesh
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### Re: Multiplication symbols

JaneFairfax,
Thanks for the post. I had learnt of this immediately on seeing your reply to the puzzle being referred. I thought that was the end of it.

Character is who you are when no one is looking.

## #3 2009-01-25 16:34:49

Ricky
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### Re: Multiplication symbols

It is also typical for a baseline dot to mean the dot product.  But I'm not entirely sure why this is posted in Euler Avenue and not in response to the puzzle... But hey Jane, mistakes happen.  Getting angry over something that can't be changed really does nothing but make it worse.

"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

## #4 2009-01-26 00:04:43

Identity
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### Re: Multiplication symbols

I prefer (2)(3) = 6, typically reserving

and
for vectors.