This Excel spreadsheet will assist you in creating customized word searches.
You select the size of word search and the answer words. Since you select the answer words, you can make the word search as hard or simple as you want (backwards, diagonal, etc).
The program will automatically fill in the blanks (everything except your answer words) with randomly generated letters. Recalculating the spreadsheet changes everything (except your answers!).
For the class or home, you can create lots of fun word searches.

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I work as the Associate Budget Director of a major Higher Education Institution. For a number of years I have taught a course on Spreadsheets and Databases.