Insert special characters using unicode in Google Spreadsheet

While trying to create IOS & NXOS keyboard shortcuts in quizlet for my students, I realized, it is pretty difficult to insert special characters in spreadsheets.

Solution:
for Google spreadsheet:
Use function "char" and use sub-function hex2dec
Get the unicode from:
http://www.unicode.org/charts/
or
http://en.wikipedia.org/wiki/Arrow_(symbol)


Illustration:
=CHAR(hex2dec("21C6"))

to get

⇄


References:
http://en.wikipedia.org/wiki/Unicode_input#In_Mac_OS
http://wiki.brandoncurtis.com/w/Inserting_Special_Characters_with_Unicode