4. Now you have to use parentheses because you are using both AND and OR. You get birds, plus either dogs or cats birds AND (dogs OR cats)
5. You get either birds and dogs together, or cats and fish together. (birds AND dogs) OR (cats AND fish)
6. Now you're going to have nested parentheses - one set inside another. You get either cats, or birds and dogs together, but not fish. (cats OR (birds AND dogs)) NOT fish
7. Can you guess what the parentheses are for? Hint: If you remember anything from algebra, think “Order of Operations.”
8. You’re using the parentheses to tell the database how to group the keywords. That lets it perform a set of calculations, which have to be done in a certain order. Without the parentheses, you‘d get only a fraction of the good search results, with a lot of bad ones mixed in.