# Comparing Decimals: Decimal War!

- Fifth Grade
- Math
- 55 minutes
- Standards: 5.NBT.A.3.B

Get your students excited and test their knowledge of comparing decimals with this fun decimal "war" game!

### Learning Objectives

Students will be able to compare two decimals by using place value to determine whether one is greater than, less than, or equal to the other.

## Lesson

### Introduction *(5 minutes)*

- Remind students of the terms
**greater than**, >,**less than**, <, and**equal to**, =. - Write the following two numbers on the board with a space between them: 123 and 23.
- Have students show a greater than, less than, or equal to sign with their arms.
- Ask students how they know that 123 is greater than 23. Many students will say because it's a "bigger" or "longer" number.
- Next, write the following two decimals on the board with a space between them: 1.23 and 2.3.
- Have students show a greater than, less than, or equal to sign with their arms.
- Many students will say that 1.23 is greater than 2.3 for the same reason as the previous example. Tell students than in this case, 2.3 is the greater number.
- Ask students to explain why 2.3 is greater. Take several examples.

### Explicit Instruction/Teacher Modeling *(10 minutes)*

- Hand out place value charts to your students, and draw a larger version of the chart on the board.
- Write in the numbers 1.23 and 2.3 in the place value chart.
- Explain to students that when you are comparing decimals, you always look at the largest place value first. In this case, it is the ones place. Have students cover up all other digits and place values so only the numerals in the ones place are showing.
- Ask students which of these two digits is greater. Once students have concluded that 2 is greater,Explain that that means that 2.3 is the greater number.
- Show students another example, such as 4.5 and 1.223. Repeat the steps to show that 4.5 is the greater number.
- Next, show students the following example: 3.25 and 3.6. Again, have students compare the ones place first.
- Tell students that this time, we can't determine which number is bigger by looking at the ones place because they both have the same value.
- Have students then uncover the tenths place. Ask students which of these two digits is greater? Once they determine that 6 is greater, explain that that means 3.6 is the greater number.
- Finally, show students this example: 5.9 and 5.900.
- As done previously, have students compare each place value, starting with the ones place. Students should determine that these two numbers are equal to each other. Point out that a blank space in the place value chart and a zero are the same value.
- Repeat with more examples if necessary.

### Guided Practice/Interactive Modeling *(20 minutes)*

- Assign students to partners. Pass out the Decimal War! cards.
- Explain the rules of war: Divide the cards evenly between the two players. Students should keep the cards face down. Each students turns over the top card at the same time. Whoever has the greatest number gets to keep both of the cards. The person who has the most cards at the end of the game wins!
- Tell students that in a case where two cards are equal to one another, each player keeps their own card.
- Encourage students to use their place value charts if needed.
- Circulate the room to ensure that students are on the right track.

### Independent Working Time *(10 minutes)*

- Have students complete the top portion of Delicious Decimals worksheet independently.
- After collecting the papers, review answers with students.

## Extend

### Differentiation

**Enrichment**: Have students create word problems that require comparing decimals. These students could also practice comparing more than two decimals.**Support**: Require students who need extra support to use the place value chart during decimal war and for independent practice. Small group help from the teacher with additional examples would also benefit these students.

## Review

### Assessment *(5 minutes)*

- Use the Delicious Decimals worksheet to determine students' understanding of comparing decimals.
- Look for the following misconceptions: Are students still choosing the longest number as the greatest number? Do students understand that the zeroes at the end of a decimal do not increase the value of the number?

### Review and Closing *(5 minutes)*

- Write a few more decimals on the board for students to compare using their arms. Give at least one example where the decimals are equal to one another.

## Teacher Tips