A search for dogs or cats would access websites in which either the word dogs or the word cats appears. The Boolean operator OR can be very useful when there are many synonyms for a concept. For example, teenagers OR adolescents OR youth will yield many more citations than any of these words by itself. NOT limits search results because it eliminates an element. Sometimes it is necessary to search a phrase .
Some search engines assume that the word AND appears between words.
For example, a search for social studies would not necessarily return results that are relevant to the curriculum area Social Studies. A good example is the term math. An elementary teacher may want to do a search for lesson plans for a third grade math lesson. Truncation allows the teacher to access Web sites that have information on math, mathematics, etc. Here are several helpful resources that will help you become proficient.