Moving from Fractions to Decimals

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4.NF.6 Use decimal notation for fractions with denominators 10 or 100.

Big Idea

In this lesson students use place value charts to explore and reason about how fractions can be changed to decimals.

Warm Up!

15 minutes

Fraction Pad

In this lesson my students are introduced to decimals for the first time. Because this is a new skill, I want to make sure students are able to connect to the concept from where they are. To do this I invite them to the carpet to see how much they already know about fractions.

I write 23/100 on the board for students to explore a bit. You all know numbers can be represented in multiple ways.  How many of you think that fractions can also be represented in different ways? All students raise their hands, but none can actually offer any suggestions on how they can be represented.  

I point to the number above the fraction bar and ask student volunteers to tell me what that number represents.  (The number 23 represents the numerator.) What does the numerator tell us? (It tells us how many parts of the whole) Great! What about the number below the fraction bar. Can anyone tell me what that number represents? ( It is the denominator, and it tells us the whole) Alright, so you guys do know about fractions. 

I go over a couple of more fraction just to make sure my struggling students understand the parts of the fraction.  I encourage students to ask questions. This will help them better understand how fractions are written.

Mathematical Practices:

MP. 8. Look for and express regularity in repeated reasoning.


Group Practice!

15 minutes

Now that my students understand fractions. I want my students to make connections between fractions with denominators of 10 and 100.  To do this I reintroduce them to the place value chart. I point to the fraction on the board. 23/100 and say, twenty-three hundredths. After that I rewrite the fraction as 0.23. Using the place value chart, I ask students to think of a way that the decimal can relate to the chart.  Some students actually want to come up and insert the numbers into the chart. So, I allow them to do so to see what they would come up with. Surprisingly students are able to insert the numbers according to their value.  To see if I can take it a step further, I ask students to give another example of a fraction that can be written in decimal form.  As students are working their way though the given instructions. I probe them a bit to make sure they are grasping the concept. I want to make sure that they know that both the fraction and the decimal has the same value.  So I write 0.23 on the board.  I ask students to think of a fraction that can correctly represent the given decimal.  Students quickly related to the concept and wrote 23/100. 


I practice this skill a bit more to make sure students can give examples and explain on their own. 

(Students used MP7 look for and make use of structure.)

Paired Practice

15 minutes

In this portion of the lesson, I ask students to move with their assigned partners. I tell them they are going to have about fifteen minutes to practice changing fractions to decimals.  I tell students not to worrying because we will be using fractions with denominators of 10 and 100 to make it easier for them to grasp the skill.  Because I want everyone to know how to say the names of fractions, I tell them to write the fraction in written form. This helps them make the connection to decimals as well.  Once they have all written the fraction, I tell them to place the digits into the correct columns on their place value chart. (Be sure that the digits correlates with the value.)  I circle the room to check for understanding and make sure students are fully engaged in their work.  I notice some students representing their fractions using illustrations.  I ask them to explain why they are using illustrations? The student says that the illustration helps him determine the parts and the whole. Since decimals are only the whole I know what number to write in decimal form. Although, other students seem to be adjusting fine some students need additional support. 

Some students represent each digit in the numerator. For instance, 23 is written 2/10 and 3/100. By looking at it from an expanded standpoint students quickly identified the value of each digit. I continue to check for understanding while students are working. I encourage them to turn and talk to their neighbor to see if they are doing anything different that can assist them in their learning. 

Share Your Findings

10 minutes

In this portion of the lesson, I want students to share what they have learned so far.  Some students demonstrate how to write fractions as decimals and use the place value chart to check their answers. I notice some students look a bit puzzled, so I encourage them to ask their classmates questions to gain a better understanding. As students take turns sharing their work, I continue to take notes. I use the notes to make sure a level of understanding is reached.