1) if nick write some thing like this 20/45 or 23*45 etc i.e. numbers are separated by any character and i don't wnat to calculate them, i want to know both numbers
This would require an ON TEXT event, and a number of checks to determine if it's a number or not. Possibly a regex would work for this, I'm not sure.
2) how can notify a nick after a time, only once, but no of nicks can be more
Huh? This only makes partial sense to me. Notifying a nick after a certain amount of time can be done using a timer.
See /help /timer
3) how can i set a script which save hash tables to file in a timed interval
Again, use a timer.
BTW: For more information regarding raws, you might want to take a look at
http://www.mirc.net/raws