Prefixes: un-, re-

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SWBAT use prefixes, un- and re-, to decipher and change the meaning of words.

Big Idea

Students learn the meaning of prefixes and how they change the meaning of base words.

Do Now

20 minutes

I told students we were going to learn about prefixes and how they can help us figure out the meaning of words without using a dictionary. I referred them to the prefix chart in the room which had the definition of the prefix and words containing the prefix. I started with un- and re- because they are common and students encounter them often at the 3rd grade reading level.

Next, I directed their attention to the SmartBoard which displayed today’s interactive lesson. I told students the definition of a base word. A base word is the simplest form of a word and has nothing added to it. Its meaning can be changed by adding a group of letters before or after it. These groups of letters are called prefixes and suffixes. We would learn about suffixes later.  I showed them examples of base words as I gave the definition. I navigated to the next page of the lesson and showed them base words with affixes added to them. I had them write the base words on their whiteboards to see if they understood the concept of base words. After a few initial errors, most students were able to write the words. I modeled underline the affixes and circling the base words. Students used this to check their answers.

I told them prefixes are found at the beginning of a word. Prefixes change the meaning of words. I told them the definition of un- and demonstrated how it changes the meaning of a word. Happy means you’re smiling and feeling good. Unhappy means you are not smiling and feeling good. Un- means not. Therefore, unhappy means not happy. I wrote a few more examples like this. I repeated the same steps with the prefix re-. We did a few activities on the SmartBoard. For example, one of the activities required students to match the word with the definition. To tell again means retell. To not lock means unlock.

Independent Practice

60 minutes

For independent practice, students worked on center activities. I downloaded and assembled them from the Florida Center for Reading Research website. There were four hands-on activities and a practice sheet. Two activities focused on identifying base words and affixes, two focused on the meaning of prefixes, and the practice sheet required students to use the definition of affixes to complete sentences with the correct word. I included the base word activity because it is important that students are able to identify them. It helps with decoding, spelling, and syllabication. As an example of one of the centers on base words, each student had a base word board. There was a stack of word cards with affixes. Students took turns pulling cards and identifying the word parts. They looked on their word board for the base word. If found, they placed the word card on top of the base word.


10 minutes

I assessed students informally as they worked in centers. I also graded the practice sheet to get an idea of how well they had mastered prefixes un- and re-. Grading was on a scale of 100. A score of 80% or higher was considered mastery.


5 minutes

To wrap up today’s lesson, I had students complete a Ticket Out the Door. I asked them to write which center was their favorite today and why. This activity calmed from all the excitement of centers, gave them time to reflect on today’s learning, and gave me feedback for future activities.