Intermath | Workshop Support
Lesson Plan

Adding Tenths

Addition of tenths and hundredths.

Grade levels

Explore the incremental steps of counting with tenths and hundredths.  Use pencil and paper to add 0.1 until you get 0.9.  How many times did you add 0.1?

On a calculator, enter the number 0.1. Continue to add 0.1 until you get 0.9. When you add another 0.1, what do you think you will get? Why? Continue to count to 4 or 5 by tenths. How many times do you have to add 0.1 to get from one whole number to the next? Try counting by 0.01. How many times do you have to add 0.01 to get from 0.01 to 0.1? Which is faster, counting by tenths to 10 or counting by hundredths to 1?

Create a spreadsheet that shows all your answers. for adding 0.1 up to 5. 


Complete a hands-on exploration using dimes and pennies. 

1) How many dimes does it take to get to $1.00?  How many pennies?

2) How many dimes does it take to get to $2.00?  How many pennies?

3) How many dimes does it take to get to $3.00?  How many pennies?

Lesson Type (lab, demo, worksheet, hands-on, other)
Combination demonstration, hands-on, and computer lab.

Estimated time
One hour

Resources & Materials
Pencil and paper, calculator, Excel, dimes and pennies. 

Students will explore the addition of tenths and hundredths.

First students will use pencil and paper to complete the addition of tenths and hundredths.  Then, students will explore the addition of tenths and hundredths using a calculator.  Next, students will show their answers by creating an Excel spreadsheet.  Finally, students will explore a hands-on application using dimes and pennies to determine how many incremental steps are necessary to equal $1.00 in dimes and pennies, $2.00 in dimes and pennies, and $5.00 in dimes and pennies.


Applicable QCC Standard(s)

Topic: Decimals
Standard: Relates decimals (through hundredths) to models using base ten blocks and grid paper.
Topic: Decimals
Standard: Using models and vertical and horizontal presentations, adds and subtracts decimals through hundredths, without and with regrouping.
Topic: Problem Solving
Standard: Given a situation, chooses the most appropriate method of computation (mental computation, paper and pencil, or calculator).
Topic: Appropriate Methods and Tools, Applications
Standard: Solves problems, reasons, and estimates throughout mathematics.
- Selects and uses problem-solving strategies such as reading the problem, drawing a picture or diagram, using trial and error, making a table or chart, looking for patterns, making a simple problem then generalizing, working backwards, etc.
-Selects and uses appropriate tools (such as mental computation, calculators, manipulative materials, paper and pencil, computer) in solving problems.
-Uses appropriate estimation strategies (such as breaking numbers apart, compatible numbers, guess and check, clustering, rounding, compensation) to check the reasonableness of results.
-Solves nonroutine problems for which the answer is not obvious.
-Relates concepts and skills to practical applications.
Topic: Research, Investigation, Data Analysis
Standard: Uses computer software and applications to research, investigate, and analyze data and to represent this information using charts, tables, graphs, or other presentation forms.

NCTM Process Standard(s)
In grades 6-8 all students should:

  • work flexibly with fractions, decimals, and percents to solve problems

  • understand the meaning and effects of arithmetic operations with fractions, decimals, and integers

  • select appropriate methods and tools for computing with fractions and decimals from among mental computation, estimation, calculators or computers, and paper and pencil, depending on the situation, and apply the selected methods

    Author & Contact
    Teresa Johnson
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