A prefix is a group of letters added to the beginning of a word to give that word a new meaning. The prefix ''re'' means to try something again, so when you add it to the beginning of ''do'' you get a new word, ''redo'', but when you're trying to figure out spelling rules for prefixes, you won't have to ask for a redo! You'll learn how in this lesson.
Did you notice what happened to the spelling of ''do'' when you added the prefix? Nothing! Adding prefixes in English doesn't change the spelling of the word. All you have to do to spell a word correctly with the prefix is write the two together without a space between them. Re + do = redo. Here's one more example. ''Hydro'' means ''water'', so if you want to talk about something that's powered by water, you put that prefix before the word. Add to ''electric'' and you get ''hydroelectric''. Prefix plus root word equals the new word.
What about double letters? There are plenty of words with prefixes that also have double letters. Look at the list below. All of these are made by writing the prefix then writing the word. Double letters are fine.
Even when you take the prefix ''mis'' and place in before the word ''spell'' you keep the double letter - ''misspell.'' It's correct to spell ''misspell'' with a double s.