'expr' command not working with option *

[Saran]

To whom so ever it may concern..

Hi,
I find that the expr command in my linux shell is not working for multiplying 
two arguments. please help me out how could i multiply two numbers in a shell 
and how could i use the command in my shell scripts..
when i type expr 2 * 3 it is giving syntax error.
whereas if i type expr 2 + 3 it is giving me the correct result '5'.

Thank you

awaiting your reply..
Saran.