Add instead of update in MySQL

Is there a way to use update to add a number to a database field instead of replacing it.

For example currently when I update a field containing a 5 with the number 6 it just replaces the 5 with a 6.

I’d really like it to just add the new number to the existing one - in this case making 11.

Any one know how?

Cheer

Dave

UPDATE TABLE_NAME SET FIELD_NAME = FIELD_NAME + NEW_VALUE WHERE CRITERIA_IS_MET