How do I write the division sign?

You can use a keyboard shortcut to make a ÷. Copy the devision sign from Kappy's answer. Go to settings> general> keyboard> shortcuts> tap the plus sign> paste the division sign on the top line, ds on the bottom lne. Tap save. Now all you have to do is tap ds and the space bar for your division sign Will appear.

The sign typically used other than in typesetting is the forward slash, i.e., "/" as in 2/4. Furthermore, the formal division sign is "÷" in all languages, not just in Japanese.

maounkhan wrote:

WHy is the division sign (such as +) only in Japanese (Kana)? Shouldn't it be in all languages that use math/operations?

You can ask Apple to add this symbol to the English (US) and other keyboards via

http://www.apple.com/feedback

In the meantime there are a number of 3rd party keyboards available in the app store which have lots of symbols for math, etc which may meet your needs.

Division is represented by '/' in mathematics.