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### Overview

This learning activity is a task presented to the class to introduce the topic of rounding.  The real-world context of the problem engages students as they learn the purpose and strategies for rounding multi-digit whole numbers using place value understanding. Students use a number line to identify benchmark numbers.

### MA19.4.9

Round multi-digit whole numbers to any place using place value understanding.

## UP:MA19.4.9

### Vocabulary

• Round
• Place value
• Ones
• Tens
• Hundreds
• Thousands
• Ten thousands
• Approximately
• Halfway point

### Knowledge

Students know:

• The relationship among positions of digits in a number and place value. They can use that knowledge to round numbers to nay place.

### Skills

Students are able to:

• Use place value strategies to round multi-digit whole numbers to any place.

### Understanding

Students understand that:

• rounding multi-digit numbers is an estimation strategy used when writing the original number as the closest multiple of a power of 10.

### Phase

Before/Engage
Learning Objectives

### Learning Objectives

Students will be able to use place value understanding to round multi-digit whole numbers.

With support, they will be able to:

• generate benchmark numbers
• determine the halfway point on the number line
• place multi-digit numbers on the number line
• choose the correct benchmark for rounding
• explain the purpose of using rounded numbers in a real-world context

### Activity Details

• Present the first slide of the Guess the Tickets slideshow to the class.  Read the task aloud.
• Have students talk to their partners or table group about possible solutions.
• As students share their solution ideas with the class, direct their discussion towards estimating, rounding, and the purpose of using "friendly" numbers.
• On the next slide, the students are scaffolded as they use a number line to round the three ticket amounts.  The first number line is fully labeled; students just need to place the ticket amount on the line and determine which way to round.  The next number line has the first benchmark but is missing the other labels.  Students must produce the benchmarks before placing the ticket amount and rounding.  The final number line is blank.  (Students can work with partners or table groups as support if needed. You may also wish to print/share this slide for students to use at their seats.)
• On the last slide, students are returned to the purpose of the task and must use the rounded ticket amounts to solve the problem.
• As a check, add all three un-rounded ticket amounts on the board to see how close the estimate is -- and to show how much easier it is to estimate with friendly numbers.
• Following this task, students should be ready for more direct instruction on rounding using place value understanding.
Assessment Strategies

### Assessment Strategies

Assessment will be observed. Check to see if (with support) students are able to:

• generate benchmark numbers
• determine the halfway point on a number line
• place multi-digit numbers on a number line
• choose the correct benchmark for rounding
• explain the purpose of using rounded numbers in a real-world context

### Variation Tips

You may extend the activity by asking students to determine about how many more tickets would be needed to purchase the toy.

### Background / Preparation

Teachers may wish to print or digitally share the slide with the number lines for student use during the activity.

### Materials and Resources

• Present the first slide of the Guess the Tickets slideshow to the class.  Read the task aloud.
• Have students talk to their partners or table group about possible solutions.
• As students share their solution ideas with the class, direct their discussion towards estimating, rounding, and the purpose of using "friendly" numbers.
• On the next slide, the students are scaffolded as they use a number line to round the three ticket amounts.  The first number line is fully labeled; students just need to place the ticket amount on the line and determine which way to round.  The next number line has the first benchmark but is missing the other labels.  Students must produce the benchmarks before placing the ticket amount and rounding.  The final number line is blank.  (Students can work with partners or table groups as support if needed. You may also wish to print/share this slide for students to use at their seats.)
• On the last slide, students are returned to the purpose of the task and must use the rounded ticket amounts to solve the problem.
• As a check, add all three un-rounded ticket amounts on the board to see how close the estimate is -- and to show how much easier it is to estimate with friendly numbers.
• Following this task, students should be ready for more direct instruction on rounding using place value understanding.