It's Close Enough: Rounding and Estimation

Kathy PetersBay District Schools

Description

Students are introduced to place value concepts as they learn how to round to the closest five, ten, and hundred.

Objectives

The student uses place-value concepts of grouping based upon powers of ten (thousandths, hundredths, tenths, ones, tens, hundreds, thousands) within the decimal number system.

Materials

-Computers with Web School Access
-Software: Math Blaster 1,Trash Zapper, Lessons 1,2,3 - Estimation
-Silver, Burdett. "Ginn Mathematics Grade 3-5," Volume 1, pages 10-13, teaching tools #10, practice page 1-4, reteaching page 1-4. (If this text is not available, centimeter grid paper and teacher instruction in rounding to the nearest ten and hundred are required.)
-Teacher recording of Marge's Diner by Gail Gibbons and teacher prepared questionaire
-Paper, pencils, crayons
-Copies of Rounding Chart and Rounding Assessment (See Associated File)

Preparations

1. Record Marge's Diner and prepare the questions.
2. Make sure computer is online and ready.
3. Copy teaching tool #10 from Silver, Burdett, "Ginn Mathematics" or use centimeter grid paper.
4. Download and duplicate copies of the Rounding Chart, one per student. (See Associated File)
5. Be familiar with Math Blaster.

Procedures

Day One (60 minutes)
1. Introduce lesson on rounding to the closest five using Web School lesson, "Just About." Use a presentation station to enable students to participate in whole group instruction.

2. Using hundred charts (teaching tool #10) (see Materials), or centimeter grid paper, review concept of closest five. Have students color code which numbers round to the closest five. Have students label this chart, "Rounding to the Closest Five."

3. Brainstorm four examples of how we use rounding and estimation in our daily lives. Using the math text (see Materials), pages 10-13 as a foundation, teach concept of rounding to the closest ten and closest hundred. Use direct instruction to review concept.

4. Students work with partners to complete R1-4 (Reinformment) (see Materials), which is rounding to the nearest ten and nearest hundred. If worksheet is unavailable, use a teacher-made activity for the same concept.

Day 2 Procedures (60 minutes)
Divide students into four groups to complete learning center activities. Rotate groups every fifteen minutes.

Learning Center One:
Listen to recording of Marge's Diner. Answer teacher-prepared questions:
1. About how many people eat in the diner each day?

2. About how much would the customers spend in one day if each person spent \$5?

3. About how much money would the diner take in during the course of one month, one year?

Learning Center Two:
1. Have students use the computer Software: Math Blaster, Trash Zapper - Estimation: Lessons 1,2,3.

2. Save student work to a file.

Learning Center Three:
Color a Rounding Chart
1. Label one "Rounding to the Nearest Ten." Using the Rounding Chart in the associated file, color code numbers that would round to the lower ten, one color. Color numbers that would round to the higher ten, another color. (For example 10-14, 20-24, 30-24 could be blue. 15-20, 25-30, 35-40 could be red.)

2. Challenge activity: Have students create a second chart that would demonstrate which numbers would round to the closest hundred.

Learning Center Four: