This is about the prefix 're-.' The prefix 're-' means 'again.' Rebuild means build again.

We are learning how prefixes change words. The prefix 'un-' means 'not.' So 'unkind' means 'not kind.'

This is about the prefix 'mis-.' The prefix 'mis-' means 'wrong.' So 'misplace' means 'place it wrong.'

We are using the prefix 'un-.' The prefix 'un-' means 'not.' So 'unsafe' means 'not safe.'

We're learning about the prefix 'pre-.' The prefix 'pre-' means 'before.' So 'preheat' means 'heat before.'

This is about the prefix 're-.' The prefix 're-' means 'again.' So 'retell' means to tell again.

This tests prefix meanings. The prefix 'pre-' means before. Preheat means to heat before cooking.

This tests CCSS.L.2.4.b (determining the meaning of a new word formed when a known prefix is added to a known word). A prefix is a group of letters added to the beginning of a word that changes its meaning. Common grade 2 prefixes: (1) UN- means "not" or "opposite" (unhappy = not happy, unsafe = not safe, unlock = opposite of lock/remove lock, untie = opposite of tie), (2) RE- means "again" (reread = read again, retell = tell again, redo = do again, rebuild = build again), (3) PRE- means "before" (preview = view before, preheat = heat before, preschool = before regular school), (4) MIS- means "wrong" or "incorrectly" (misspell = spell wrong, misbehave = behave wrong, misplace = place wrong). When you know what a prefix means and what the base word means, you can figure out what the new word means by combining them: prefix meaning + base word meaning = new word meaning. This helps you understand many new words without looking them up. Choice C is correct because it combines the prefix meaning un- = not with the base word meaning happy = feeling good to get unhappy = not feeling good. The prefix un- added to happy changes the meaning to not happy, following the predictable pattern for this prefix. Choice B shows thinking un- means "very" instead of "not." Second graders often think un- means "very" instead of "not," forget that re- means "again," ignore the prefix and just use base word meaning, confuse which prefix means what, think unhappy means "very happy," think reread means just "read" without the "again," reverse prefix meanings (unlock = to lock). To help students: Create prefix meaning chart: UN- = not/opposite (unhappy, unsafe, unfair, unlock, untie, unwrap), RE- = again (reread, retell, redo, rewrite, rebuild, replay), PRE- = before (preview, preheat, pretest, preschool), MIS- = wrong (misspell, misbehave, misplace, misunderstand). Teach the formula: PREFIX meaning + BASE WORD meaning = NEW WORD meaning. Example: un- (not) + happy (feeling good) = unhappy (not feeling good).

This tests CCSS.L.2.4.b (determining the meaning of a new word formed when a known prefix is added to a known word). A prefix is a group of letters added to the beginning of a word that changes its meaning. Common grade 2 prefixes: (1) UN- means "not" or "opposite" (unhappy = not happy, unsafe = not safe, unlock = opposite of lock/remove lock, untie = opposite of tie), (2) RE- means "again" (reread = read again, retell = tell again, redo = do again, rebuild = build again), (3) PRE- means "before" (preview = view before, preheat = heat before, preschool = before regular school), (4) MIS- means "wrong" or "incorrectly" (misspell = spell wrong, misbehave = behave wrong, misplace = place wrong). When you know what a prefix means and what the base word means, you can figure out what the new word means by combining them: prefix meaning + base word meaning = new word meaning. This helps you understand many new words without looking them up. Choice B is correct because it combines the prefix meaning un- = not with the base word meaning happy = feeling good to get unhappy = not feeling good. The prefix un- added to happy changes the meaning to not happy, following the predictable pattern for this prefix. Choice C shows thinking un- means "very" instead of "not." Second graders often think un- means "very" instead of "not," forget that re- means "again," ignore the prefix and just use base word meaning, confuse which prefix means what, think unhappy means "very happy," think reread means just "read" without the "again," reverse prefix meanings (unlock = to lock). To help students: Create prefix meaning chart: UN- = not/opposite (unhappy, unsafe, unfair, unlock, untie, unwrap), RE- = again (reread, retell, redo, rewrite, rebuild, replay), PRE- = before (preview, preheat, pretest, preschool), MIS- = wrong (misspell, misbehave, misplace, misunderstand). Teach the formula: PREFIX meaning + BASE WORD meaning = NEW WORD meaning.

This tests CCSS.L.2.4.b (determining the meaning of a new word formed when a known prefix is added to a known word). A prefix is a group of letters added to the beginning of a word that changes its meaning. Common grade 2 prefixes: (1) UN- means "not" or "opposite" (unhappy = not happy, unsafe = not safe, unlock = opposite of lock/remove lock, untie = opposite of tie), (2) RE- means "again" (reread = read again, retell = tell again, redo = do again, rebuild = build again), (3) PRE- means "before" (preview = view before, preheat = heat before, preschool = before regular school), (4) MIS- means "wrong" or "incorrectly" (misspell = spell wrong, misbehave = behave wrong, misplace = place wrong). When you know what a prefix means and what the base word means, you can figure out what the new word means by combining them: prefix meaning + base word meaning = new word meaning. This helps you understand many new words without looking them up. Choice A is correct because it combines the prefix meaning re- = again with the base word meaning read = to look at and understand words to get reread = read again. The prefix re- added to read changes the meaning to read again, following the predictable pattern for this prefix. Choice B shows using the wrong prefix meaning, thinking un- means not read instead of re- for again. Second graders often think un- means "very" instead of "not," forget that re- means "again," ignore the prefix and just use base word meaning, confuse which prefix means what, think unhappy means "very happy," think reread means just "read" without the "again," reverse prefix meanings (unlock = to lock). Example: un- (not) + happy (feeling good) = unhappy (not feeling good). Practice with known words: Start with base word students know well ("happy"), add prefix ("un-"), guide through combining meanings ("un- means not, happy means feeling good, so unhappy means not feeling good").