Teachers, who are adept in the subject, rack their brains and generate new worksheets with a support answer key to guide the instructor. There is no limit to the number of worksheets you generate for the class or tutorials and they can be used for distribution purposes.
Who's Fault? Is it his fault that he lacks confidence with word problems? Not entirely. Our actions, as educators, seem to imply a belief that solving word problems should come more naturally than simpler operations like arithmetic and algebra. Many parents and teachers feel justified in encouraging (i.e. forcing) a child to work hundreds or thousands of math worksheets, drill multiplication tables, long division... but few encourage solving hundreds of story problems. One suspects that the relative ease of creating and checking ordinary math worksheets keeps the focus of math education on simple, atomic operations at the expense of more holistic story problems.