*See Supplemental Resources s4

Math Lesson: Rounding Numbers Grade Level: 3

Lesson Summary: The teacher will begin by leading a discussion about situations when it is necessary to know an exact amount of an item and situations when it is necessary only to know an approximate amount. Students will learn how to round numbers to the nearest ten, hundred, and thousand by using a simple graphic and practice the skill with the teacher and then independently. Advanced learners will create their own problems that involve rounding. Struggling learners will be provided with a graphic that will help them round independently.

Lesson Objectives:

The students will know…  How to round numbers though the thousands place.

The students will be able to…  Round numbers through the thousands place.

Learning Styles Targeted:

Visual Auditory Kinesthetic/Tactile

Pre-Assessment: Tell students that sometimes a situation calls for the need to know the exact amount of something. For example, if a large group of students were going to a play, the teacher would need to know exactly how many tickets to order for all the students. If the teacher ordered too few, some students wouldn’t be able to go, but if the teacher ordered too many, the cost would be too great. Ask students to share some other examples of times when it’s necessary to know the exact amount of something. Tell students that sometimes a situation calls for the need to know an approximate number of something. For example, if a parent were planning a large birthday party and was planning to serve pizzas, it would be impossible to know exactly how many pieces of pizza were needed. It’s necessary for the parent only to know an approximate amount of pizza that should be ordered. Ask students to share some other examples of times when it’s necessary only to know an approximate amount of something.

Whole-Class Instruction

Materials Needed: Teaching Points PowerPoint presentation*, computer connected to a projector, Example Board* for teacher reference, 1 whiteboard per student, 1 dry-erase marker per student, 1 tissue per student, 1 copy of the Independent Practice* per student, 1 pair of scissors per student, 1 bottle of glue or glue stick per student, writing utensils

Procedure:

1) Draw the symbols = and ≈ on the board. Ask students what they notice about them. Elicit responses from students. Explain to students that they are both types of equal signs. One (=) shows an exact answer, and the other (≈) shows an approximated answer. Tell students that today they will be learning how to round numbers from an exact answer to an approximated answer.

2) Project the first slide of the Teaching Points PowerPoint presentation, and read the problem aloud. Explain to students that the word “about” signals that the question is not asking for an exact answer, but a rounded answer. Tell students that you are going to show them away to round 32 to the nearest ten so that it is an estimated answer instead of an exact answer. Draw a small hill on the board like the one shown on the Example Board. Tell students that because you are going to round 32 to the nearest ten, that you must think of the two multiples of ten that 32 comes in between. Count by tens to model for students what numbers you are referring to. Write 30 and 40 at the beginning and ending of the hill. See the Example Board in supplemental resources, if

Copyright © 2010 Study Island - All rights reserved. necessary. Explain to students that are going to use the hill to help you figure out if 32 is closer to 30 or 40. Point to the top of the hill, and tell students that the peak represents the middle number between 30 and 40. Ask students what number is halfway in between the two, and elicit responses until a student says, “35.” Record 35 at the peak. Call on a student to tell you if 32 would be come before or after the peak of the hill. Elicit responses, and draw a point on the hill that represents 32. See the Example Board in supplemental resources if necessary. Have students imagine the point at 32 is a ball. Ask students if the ball would roll back down to 30 or over to 40. Elicit responses, and circle 30. Explain to students that 32 rounds down to 30 because it’s closer to 30 than 40.

3) Give each student a whiteboard, a dry-erase marker, and a tissue as you project the second slide from the Teaching Points PowerPoint presentation. Tell students that they will now have a chance to practice rounding to the nearest ten. Read aloud the situation on the slide, and lead them through drawing and labeling the hill before rounding 56 to the nearest ten. Repeat for slide 3. Make sure that students understand that when a number is halfway between, that it rounds up.

4) Project slide 4, read it aloud, and explain to students that a number can also be rounded to the nearest hundred. Repeat the teaching process of helping students draw the hill, label it, and round for slides 5-6.

5) Project slide 7, read it aloud, and explain to students that a number can also be rounded to the nearest thousand. Repeat the teaching process of helping students draw the hill, label it, and round for slides 8-9.

6) Take up whiteboards, markers, and tissues from students. Give each student a copy of the Independent Practice, explain the directions, and allow students to work independently.

Advanced Learner

Materials Needed: 3 index cards per student, writing utensils

Procedure:

1) Gather advanced learners together, and tell them that they will be creating their own problems that involve rounding that are similar to the ones they read on the PowerPoint presentation during the lesson. Ask students to brainstorm some situations in which you would only need to know an approximate number instead of an exact number. Allow several students to share their answers.

2) Give each student 3 index cards, and explain to students that they must write 3 problems that involve rounding. Remind students that they should use words like “about,” “estimate,” and “approximately” in their questions to signify that they are asking for a rounded answer. You may want to write these words on the board. Tell students that they should write the question on the front of the card and the answer on the back.

3) Allow students to work independently. When all students have finished, ask each student to share one of their questions aloud. The sharing student should call on a classmate to answer his/her question.

Struggling Learner

Materials Needed: 1 copy of the Independent Practice* per student, 1 pair of scissors per student, 1 bottle of glue or glue stick per student, 1 copy of the Struggling Learners Aid* per student, 1 copy of the Struggling Learners Aid* to project under a document camera, a document camera connected to a projector

Procedure:

Copyright © 2010 Study Island - All rights reserved. 1) Give each student a copy of the Independent Practice and a copy of the Struggling Learners Aid. Project a copy of the Struggling Learners Aid under a document camera, and tell students that they will use this to help them answer the questions. Go through 1-2 problems with students, reminding them how to use the graphics to help them round. When students are able to use the graphics on their own, allow them to work independently. Students should turn in their rounding graphics with their Independent Practice. *see supplemental resources