3*5/3*5 versus 3*5:3*5 in Wolfram Alpha

[sergioduartesilva (Sergio da Silva)]

Hello fellows

Why WolframAlpha give the answer 25 (correct) for 3x5/3x5 but 1 for 3x5:3x5 ?

Thanks.

[gianlucagorni]

I don’t know why, but Wolfram|Alpha gives the two symbols / and : for division two different precedences: / has high precedence, : ha low precedence.

Also, if I type a b/c d when the MathInput button is inactive, it is interpreted as a(b/c)d. If I type the very same characters a b/c d with the MathInput button active, it is interpreted as a(b/(c d)).

Caveat user.

[gianlucagorni]

One more thing: if I type a b/c d in a text editor and paste it into Wolfram|Alpha with the MathInput button active, it is interpreted as a(b/c)d, because the two-dimensional input does not get triggered by the pasting.

[danl (Daniel Lichtblau)]

I believe it is common for ratio operator precedence to group everything to the right apart from everything to the left, unless and until a subsequent ratio sign (colon) is encountered.