Teaching the Common Core Math Standards With Hands-On Activities, Grades 3-5 (27 page)

Closure

Discuss students' results.

Answers

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• Comparisons may vary. Two correct answers are
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Number Form Cards

Number and Operations in Base Ten: 4.NBT.3

“Generalize place value understanding for multi-digit whole numbers.”

3. “Use place value understanding to round multi-digit whole numbers to any place.”

Background

An understanding of place value is essential to rounding numbers. To round a number, students must first find the digit to the right of the place they are rounding to. They must then follow the rules for rounding:

• If the digit to the right of the digit to be rounded is less than 5, the digit in the place to be rounded stays the same. Change any digits to the right of that digit to zero.
  
• If the digit to the right of the digit to be rounded is 5 or more, add 1 to the digit in the place to be rounded. Change any digits to the right of that digit to zero.
  
• If 9 is in the place to be rounded, and the number to its right is less than 5, 9 stays the same. Change any digits to its right to zero. If the number to the right of 9 is 5 or more, add 1 to the 9. Because
  change 9 to zero and add 1 to the digit to the left. Change any digits to the right of the rounded number to zero.
  

Activity: Rounding Numbers

This is a two-day activity.
Working in groups, students will be given two numbers. They will create a poster on the first day and, using their poster as a visual aid on the second day, will explain to the class how to round the two numbers they were given.

Materials

Large poster paper; rulers; markers; crayons for each group.

Procedure

Day One

1.
Review the steps for rounding with your students. Provide some examples, such as the following:

• Round 375 to the nearest ten: 380.
  
• Round 6,436 to the nearest hundred: 6,400.
  
• Round 58,721 to the nearest thousand: 59,000.
  

2.
Explain that each group will be given two numbers, one that must be rounded up and one that must be rounded down. Students will detail the procedure for rounding each on poster paper and then present their work to the class.

3.
Suggest that students brainstorm ideas on how to design their posters before beginning work. To clarify their ideas, they should do a “rough” design on a separate sheet of paper first.

4.
Provide each group with two numbers. You may select numbers of your own or you can use these: