We are finding base words. The base word is the main word without prefixes or suffixes. In unlock, the base word is lock.

This tests finding base words. The base word in helped is help. The -ed is the suffix at the end.

We are learning about suffixes. The suffix -ly tells how something is done. Quickly means in a quick way.

We are learning about suffixes. The suffix -less means without something. When you are careless, you are without care.

This tests what suffixes mean. The -er in teacher means a person who. A teacher is a person who teaches.

This question tests 2nd grade ability to decode words with prefixes and suffixes (CCSS.RF.2.3.d). Prefixes are word parts added to the beginning; suffixes are word parts added to the end. The suffix -ed means a past action or something that happened already. When you add it to a base word like play, it changes the time: play means to have fun in a game, so played means you did that in the past. Choice C is correct because -ed tells you it happened already in played, and the base word is play with -ed added to the end; together they mean the action is over. Choice A is incorrect because it confuses -ed with -ing, which means happening now; this error happens when students mix up suffix meanings for time. To help students, use color coding like [play] + [ed] = played, practice covering the suffix to reveal the base word, and use word building with cards to show how -ed changes the tense.

This question tests 2nd grade ability to decode words with prefixes and suffixes (CCSS.RF.2.3.d). Prefixes are word parts added to the beginning; suffixes are word parts added to the end. The prefix un- means 'not' or the opposite of something. When you add it to a base word like safe, it changes the meaning: safe means protected from harm, so unsafe means not safe or dangerous. Choice A is correct because 'not safe' matches unsafe, and the base word is safe with un- added to the beginning; together they mean the opposite of safe. Choice B is incorrect because it confuses un- with re-, which means 'again'; this error happens when students don't recognize prefix meanings or confuse them with others. To help students, use color coding like [un] + [safe] = unsafe, practice with pictures showing safe vs. unsafe situations, and make charts of un- words to show how it changes meanings to opposites.

This question tests 2nd grade ability to decode words with prefixes and suffixes (CCSS.RF.2.3.d). Prefixes are word parts added to the beginning; suffixes are word parts added to the end. The prefix un- means 'not' or to reverse an action. When you add it to a base word like lock, it changes the meaning: lock means to secure something closed, so unlock means to reverse that or make it not locked. Choice B is correct because un- means 'not' in unlock, as in not locked, and the base word is lock with un- added to the beginning; together they mean to open something that was locked. Choice A is incorrect because it confuses un- with re-, which means 'again'; this error happens when students mix up prefix meanings or don't recognize how un- changes the word to its opposite. To help students, use visual breakdowns with color coding like [un] + [lock] = unlock, teach prefix meanings explicitly such as un- = not, and practice with familiar base words by covering the prefix to reveal the base word.

This question tests 2nd grade ability to decode words with prefixes and suffixes (CCSS.RF.2.3.d). Prefixes are word parts added to the beginning; suffixes are word parts added to the end. The suffix -ful means 'full of' or having a lot of something. When you add it to a base word like help, it changes the meaning: help means to give support, so helpful means full of help or likely to provide support. Choice B is correct because helpful means 'full of help,' and the base word is help with -ful added to the end; together they describe someone who gives a lot of support. Choice A is incorrect because it confuses -ful with less, like without; this error happens when students don't recognize how -ful adds a sense of abundance. To help students, teach suffix meanings with charts like -ful = full of, use examples with pictures showing before/after like a helpful friend, and practice word families to avoid confusion with similar suffixes.

This question tests 2nd grade ability to decode words with prefixes and suffixes (CCSS.RF.2.3.d). Prefixes are word parts added to the beginning; suffixes are word parts added to the end. The prefix re- means 'again' or to do something back. When you add it to a base word like read, it changes the meaning: read means to look at and understand written words, so reread means to read again. Choice A is correct because re- means 'again' in reread, and the base word is read with re- added to the beginning; together they mean to read something once more. Choice B is incorrect because it confuses re- with un-, which means 'not'; this error happens when students don't recognize the specific meaning of re- or take only part of the word. To help students, start with familiar base words and make word family charts showing base + different prefixes, use pictures to show before/after like reading a book then rereading it, and watch for confusion between similar prefixes like un- and re-.