## Rounding

### Jennifer CatlettBay District Schools

#### Description

Students round to estimate greater sums.

#### Objectives

The student provides and justifies estimates for real-world quantities.

#### Materials

-Computer with Internet access for Student Web Lesson
-Number lines
-Quantity list of items
-Reteach page R3-2 (or any applicable practice page)
-Math journals

#### Preparations

2. Make quantity list items sheet.
3. Xerox R3-2 (or any applicable practice page).
4. Create number lines.
5. Check the Internet stations to verify connectivity.

#### Procedures

1. Use an overhead number line (Transparency #16 from SILVER BURDETT GINN MATHEMATICS, Grade 3, Volume 1).

2. Write 'Round 13' on the transparency.

3. Draw a red line on the number line from 13 to 10.

4. Draw a blue line on the number line from 13 to 20.

5. Ask: Is 13 located closer to 10 or 20?

6. Discuss and practice rounding more numbers to the nearest ten.

7. Discuss and practice rounding numbers to the nearest hundred using a number line.

Group Work:
Divide the students into five groups for centers. Try to rotate the groups every 10-15 minutes.

Center #1: Students complete Just About, a Student Web Lesson on estimation.

Center #2: Students practice rounding numbers to the nearest ten using number line tapes.

Center #3: Students practice rounding to the nearest hundred using a restaurant take-out menu (\$).

Center #4: Students practice rounding to the nearest hundred using a teacher-made list of items (quantities).

Center #5: Students complete a practice page such as Reteach R3-2 (SILVER BURDETT GINN MATHEMATICS, Grade 3, Volume 1) and then check their answers together.

Wrap-up:

2. Discuss what they have learned about rounding to the nearest ten and to the nearest hundred.

3. Discuss the term 'estimating' and when it might be used in real life.

4. Review examples of rounding on the board.

5. Have each student complete a math journal entry independently. Write a list of numbers on the board for students to round to the nearest ten and the nearest hundred.

#### Assessments

Teacher observation of:
1. Student participation
2. Math journal entry
3. Completed and checked Reteach page

#### Extensions

This would be a good lesson as an introduction to pages 82-83 in our new Math series. These pages deal with estimating greater sums. (SILVER BURDETT GINN MATHEMATICS, Grade 3, Volume 1)