Tiffany Hale
Elementary Mathematics
Material Type:
Upper Elementary
  • Adding Decimals
  • Lesson Plan
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    Adding Decimals Lesson Plan

    Adding Decimals Lesson Plan


    In this lesson students will learn how to add decimals to the hundredths place.




    Image by Tiffany Hale


    In this lesson students will be learning how to add decimals while ordering pizzas with variable toppings.  This face-to-face lesson should take 45-60 minutes.  

    By: Tiffany Hale

    Image by: Tiffany Hale


    Background for Teachers

    To teach this lesson, you will need an understanding of place value including decimals. This lesson should follow an exploration lesson of adding decimals using concrete models or drawings and strategies based on place value.

    Students may struggle to remember that there is no oneths place.  Review the dollar and cent symbols and how they are used. 


    Step 1 - Goals and Outcomes

    Step 1 Goals and Outcomes


    Learning Intentions:

    • Students will be able to use their understanding of place value to add decimals in real world application.

    Success Criteria:

    • Students will be able to add decimals to the hundredths place using monetary amounts.


    Step 2 - Planning Instruction

    Step 2 Planning Instruction

    Student Background Knowledge

    • Prior to this lesson, students will need to have an understanding of place value with decimals to the hundredths place.  

    Materials Needed for Each Student:

    • worksheet(s)
    • highlighters/colored pencils (3 different colors)
    • pretend money (optional)
    • base ten blocks (optional)

    Strategies for Diverse Learners

    Some students may find it helpful to use manipulatives such as base ten blocks or pretend money.  I have also included a worksheet with simpler problems and an optional page with place value tables. 

    Step 3 - Instruction

    Step 3 Instruction

    Teacher Model:  Choose a topping to add to the starting price of the pizza ($5.99). Note: The pizza topping prices are intentionally written with many zeros missing in the ones place and hundredths place. This is to ensure that students are stacking the numbers correctly before adding them.


    Color/highlight the digits in the hundredths place (pennies) pink, the digits in the tenths place (dimes) yellow, and the digit in the ones place (dollar bills) green. (Any colors work, these are just the colors I like to use.)   Draw a table and highlight three columns with the same colors used previously. Name the place value as you highlight each value.


    Next stack the digits on top of each other keeping the pennies in the pink column, the dimes in the yellow column, and the dollar bills in the green column.  Make sure to place the decimal in the correct spot. 


    Then add the pennies first.  If you add the hundredths and there are more than 10 pennies, you will need to exchange those 10 pennies for a dime.  If any pennies remain, they stay in the  pennies column.   Place the dime in the dimes column.  To do this write a +1 at the top of this column and highlight it yellow. 


    Next, add all the dimes together.  If they combine to make more than a dollar, exchange 10 of those dimes into a dollar bill and add a +1 on top of the ones column and highlight it green.  Make sure to leave the remaining dimes in the tenths column

    (See Adding Decimal Example in Resources)

    We Do Together: Pick an additional topping to add to the new price of the pizza. Have the students help highlight the digits and place them in the correct columns.  Then solve the problem together.   


    We Do Together: Pick an additional topping to add to the new price of the pizza. Remind the students to use their highlighters and have them try to solve the problem on their own.  Then have them share their answer with their neighbor and explain/show how they solved it.  If students need more practice add an additional topping to the pizza.  Some students may find it helpful to use manipulatives such as base ten blocks or pretend money.


    You Do: Students complete the worksheet. Remind them that they may use concrete models or drawings and other strategies based on place value to solve these problems.  There are challenge problems on the bottom of the worksheet for students who finish early.  


    When students finish, they need to find a classmate to check their work. They can switch papers and double check each other’s math work, or they can explain to their classmate how they solved each problem.


    Debrief:  As a class, determine which order was the most expensive and the order that was the least expensive.  Have a few students share how they found the price of one of the pizzas they ordered or the total amount of money needed for the all three pizzas.   Choose students who use different strategies and draw attention to connections between these strategies.  Remind them to use the place value terminology while they are sharing.  

    Step 4 - Assessments

    Step 4 Assessments


    Make observations during the practice part of the lesson to determine how many problems to work through together. While students are completing the worksheet, note which student may still be struggling and provide extra scaffolding. Allow students to share their learning with peers.  Give a summative quiz at the end of the lesson to gauge student mastery. They may use concrete models or drawings and other strategies based on place value to solve these problems.