### Lesson plan

# Dividing Decimals By Powers of 10

#### Learning Objectives

- Students will divide decimal numbers by powers of 10 and explain decimal placement patterns in the quotient.

The adjustment to the whole group lesson is a modification to differentiate for children who are English learners.

#### Introduction

*(5 minutes)*

- Show your students the following problem
**37.5 ÷ 10**.^{2} - Have your students brainstorm any details they understand about the expression and note their answers on a chart paper.
- Read the learning objective aloud to the class.

#### Explicit Instruction/Teacher modeling

*(10 minutes)*

- Review the concept of exponents as powers of ten, connecting them to thoughts that may have been previously shared on the chart paper.
- Demonstrate the procedure for calculating the power of 10 as a whole number equivalent. (For example,
**10**is (^{2}**10 x 10**), and (**10 x 10**) is equal to the whole number 100.) - Note that a whole number like 100 has no exponents and no decimal.
- Using a calculator, model solving
**37.5 ÷ 100**for your class. - Share the answer, or quotient: 0.375.
- Note the movement of the decimal point in the quotient (0.375) compared to the dividend (37.5).
- Point out that the decimal in the answer has moved two places to the left.
- Ask your students to turn and talk to a partner and describe any patterns they notice in the movement of the decimal and
**37.5 ÷ 10**.^{2} - Have your students share out their ideas to the whole class and make any connections to previous shared information on the chart paper.

#### Guided Practice

*(10 minutes)*

- Show your students the following problem:
**37.5 ÷ 10**.^{4} - Calculate
**10**as a whole number equivalent:^{4}**10**is (^{4}**10 x 10 x 10 x 10**), which is equal to 10,000. - Instruct your class to solve
**37.5 ÷ 10,000**with a calculator. - Tell them to note the movement of the decimal point in their quotient and observe the new position of the decimal from the dividend.
- You should observe that the decimal in the answer has moved four places to the left.

#### Independent working time

*(15 minutes)*

- Distribute the Powers of 10: Division worksheet, and review the instructions.
- Explain that students will see the powers of 10 as whole numbers, find the quotient to the division problem and then describe any recognizable patterns of decimal movement.
- Tell students they can use calculators and review any previously shared information on the chart paper that enriches their understanding.
- Answer any clarifying questions about the assignment.
- Divide the students into pairs or small groups to complete the Powers of 10: Division worksheet.
- Circulate the room and guide students with leading questions as needed.

#### Differentiation

**Enrichment:**

- Have students add an extra digit of their choice on each dividend of the Powers of 10: Division worksheet.

**Support:**

- Refer students to information on the chart paper to reference as they have questions.
- Use the ESL version of the worksheet as needed.

#### Assessment

- As you walk around the room performing check-ins, ask clarifying questions and gauge student awareness of the lesson objective and procedures.
- Collect and review practice sheets if desired.

#### Review and closing

*(5 minutes)*

- Have students check their answers with at least two other students and discuss answers that don't match.
- Call the class to attention and ask if anyone wants to share missing parts of a scaffolded sentence frame similar to this one: "I observed
. My conclusion about today's assignment is that when you divide a decimal number by a power of 10,**____**. Post the sentence frame in a place where the whole class can see it."**____** - Collect student work and review at another time to make a note of any other academically evaluative criteria.