Lesson: Introduction to Rounding

Tara Smith E.l. Haynes Pcs Washington, DC
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Lesson Objective

SWBAT define key terms for rounding.

Lesson Plan

Materials Needed: DN Worksheet, white board, dry erase markers, pencils, GP Worksheet, rulers, Key Words for Rounding sheet, 4 objects per student to measure length (approximate size of a twizzler)
Vocabulary: rounding, estimation, actual, rounding off
Do Now (3 -5 min): Teacher hands out multiplication worksheet for students to complete independently. Students struggling with multiplication should be encouraged to draw out each problem.
Opening (2 -3 min): Teacher quickly reviews answers to the Do Now and then says, “Today, we are beginning a new unit. We will be learning about rounding numbers and how it can make estimation easier. Today we are going to focus on the principles of rounding.  By the end of this lesson, you will know key vocabulary for rounding and will have practiced rounding using a ruler .”
Direct Instruction (10 min): Teacher begins “Today we are learning about rounding. Before we begin I want to explain what rounding is and why it is important that you know it. Rounding is the process of replacing a numerical value with another value that is approximately equal but is simpler, or more explicit representation. Rounding is often done on purpose to obtain a value that is easier to write and handle than the original.  [ Teacher write the following 2 numbers on the board: 257 and 260]. I will explain in more detail today and tomorrow, but if I were to round 257 to the tens place, I would round it to 260. It is important to round because it makes number to work with in our head, because it allows us to quickly get an answer that is close to the actual answer. Let’s review the vocabulary to help us understand the purpose of rounding.” Teacher writes the following words on the board:
The teacher reviews these definitions using Key Words for Rounding. The teacher should use the words in a sentence and give examples for the students. The teacher then continues, “There are many ways we use rounding in our everyday life. Tomorrow, we will be seeing how we use rounding in our everyday life. Today we will begin to understand how we round. Rounding is basically determining which number a given number is closer to within the 10s system. When you round you only round based on the tens system. For example, if I had $8 am I closer to $10 or $0? [$10]. Great! Let’s do another, if I have $5 am I closer to $10 or $0? [Answers will vary]. Hmmm, this is a tricky one, because it is right in the middle. The rule with rounding is that if it is 5 or above you round up, so the correct answer would be 10. Did you hear me say round up? You will also hear me say round down. This refers to making the number bigger or smaller. In both cases we made the number bigger.”
Guided Practice/ Independent (10 - 18 min): The teacher continues, “Ok, so now it is your turn! We are going to practice rounding by measuring items with these rulers. You will need to measure the 4 objects and then write down the actual and rounded amount. Let me do the first one with you so you know how to do it.”
The teacher picks one of the items out of the bag, and measures it. The teacher should model how to correctly measure something with the ruler, and then count out loud while determining the object’s length. On the board the teacher should write, actual size and rounded size. The teacher should make sure to use the vocabulary of rounding up or down depending on the item. The teacher should complete one more object with the students and then let the students begin rounding the objects in their bag.
Closing (2-3 min): Teacher calls the attention of the students back toward the front of the class to quickly review the answers to the Independent Practice worksheet/ ask what we learned about.

Lesson Resources

Key Works for Rounding   Exemplar
GP Lesson 1   Classwork
DN multiply single digit   Starter / Do Now


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