Unit II: Operations with Models
2018 ETAP 623 Home Page | Teaching Fractions and Number Sense
Return to: Unit I: Basics of Fractions
Unit II: Operations with Models
Lesson 4: Adding and Subtracting Fractions with Models
Lesson Notes
When students make the connection that they need equivalent fractions of the same size in order to add fractions, then they may explore common denominators. This is what happens with modeling. When the fractions are modeled, then common denominators are generated. If students have already learned the LCM from the sixth grade standards, then this is a time to let them know the lowest common denominator is going to be the LCM. If not, have students skip count to see what number they have in common first. Ask them how many common denominators there are. Since there are an infinite number of common denominators, we want to pick the first number, or multiple, that they have in common. Students can use other common denominators, but they will usually have to do more work like having to simplify their answer.
When subtracting fractions, students will also make the connection that the fractions need to have the same denominator. Have students realize that the answer to a subtraction problem would be the difference in the heights of the fraction blocks or the length of the tiles. If students are having trouble, have them find the difference between the heights of students, so that they can see the difference is the space above the shorter student and the top of the head of the taller student. Continue to have them use equivalent fractions and common denominators to subtract fractions.
Objectives
- Students will add and subtract fractions using modeling.
Task I
Watch the Adding & Subtracting Fractions using Manipulatives on EdPuzzle that is connected to our google Classroom Page. If you have not yet joined our class, you may use the link: Lesson IV Video I
Task II
Watch the Adding & Subtracting Fractions using Models on EdPuzzle. If you have not yet joined our class, you may use the link: Lesson IV Video II
Lesson 5: Multiplying Fractions with Models
Lesson Notes
Multiplying fractions can be done modeling them. Just like adding and subtracting, we want to draw out the rectangle and split it both horizontally and vertically. Remind students that multiplication is repeated addition. In the case of 4x3, this means that we have 4 groups of 3. Thus, 3+3+3+3=12. When we draw the rectangle to do ¾ times ½ , we are look to find three-fourths of one-half. So when we draw the rectangle, we want to look at what is ¾ of ½ . This is a great visual for learning how to multiply fractions.
Objectives
- Students will multiply fractions using modeling.
Task III
Watch the Multiplying Fractions using Models on EdPuzzle. If you have not yet joined our class, you may use the link: Lesson V Video I
Lesson 6: Dividing Fractions with Models
Lesson Notes
Dividing fractions can be done by modeling, also. Students can also use common denominators. Remember that fractions can mean division and division means making groups. With common denominators, students can use this to divide fractions. For example, ⅚ divides by ⅙ means how many groups of ⅙ can you make out of ⅚. This is also a good place to use a numberline or rectangle to see that you can make 6 groups of ⅙ out of ⅚ . When drawing the pictures as shown in the video, students might make the connection to the previous videos that when we split up the rectangle both horizontally and vertically, what we are really doing is finding common denominators. Then we are actually dividing fractions just like we would the standard way for multiplying fractions.
Objectives
- Students will divide fractions using modeling.
Task IV
Watch the Dividing Fractions Part I (using Models) on EdPuzzle that is connected to our google Classroom Page. If you have not yet joined our class, you may use the link: Lesson VI Video I
.jpg)
Task V
Watch the Dividing Fractions Part II (using Models) on EdPuzzle. You may use the link: Lesson VI Video II
Task VI
Quiz II
Now that you have completed this Unit, please take the summative assessment using Quizizz using code: 495853
Task VII
Writing Journal
Now write in your journal what you have learned from this unit. Be sure to reflect on what you learned and what questions you have. Try creating your own fraction problems and answer them using models.