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FFF.1 Spell words with the prefixes re- and un-

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What are prefixes?

Prefixes are word parts added to the beginning of a base word. They change the meaning of the base word.

Examples:
  • happy → unhappy
  • do → redo
Note

Think of a prefix as a clue at the start of a word that changes what the word means.

The prefix “un-”

The prefix un- means “not” or “the opposite of.” Adding un- to a word makes it negative.

Examples:
  • kind → unkind (not kind)
  • fair → unfair (not fair)
  • lock → unlock (to open something that was locked)
Note

When you see a word with un-, try saying “not” before the base word to check the meaning.

The prefix “re-”

The prefix re- means “again” or “back.” Adding re- to a word shows that something is repeated.

Examples:
  • read → reread (to read again)
  • build → rebuild (to build again)
  • turn → return (to give back)
Note

When you see a word with re-, try saying “again” before the base word to check the meaning.

How prefixes change word meaning

Prefixes change the meaning of a word but do not usually change its spelling. Knowing what prefixes mean helps you understand new words.

Examples:
  • happy → unhappy (opposite meaning)
  • start → restart (happens again)
  • tie → untie (opposite action)
Note

If you know the base word, adding un- or re- helps you figure out the new meaning quickly.

Using prefixes in sentences

Practice reading and writing sentences with words that have prefixes to understand them better.

Examples:
  • “The test was unfair.” (not fair)
  • “I will reread the story.” (read again)
  • “He unlocked the door.” (opened what was locked)
Note

Ask yourself: Does the prefix make the word mean “not” or “again”? This helps you check if the word makes sense in the sentence.