Math: Multiplying Fractions
Objectives:
Method:
I started the lesson with a warm up. We were just beginning the new chapter, so we began with a facts check in using a Mad Minute.
Using the examples from the Math In Focus: Lesson 4.1, I created a worksheet for the girls to write on to model the concept behind multiplying fractions. I projected the sheet onto the white board and we used different colored markers and highlighters to demonstrate how multiplying fractions is the same as finding a fractional part of the other fraction.
I said, "Which way shows fourths? Color in 1 row to show 1/4. Here there are tally marks to show 1/4. Which way shows thirds? Color in 2 columns to show 2/3. How many units are in the whole rectangle? What fraction is both purple and has tally marks? 2/12 which is the same as 1/6." We followed that same dialogue for the next few examples. After completing a few more, I asked the girls if they noticed anything.
Someone said, "The total number of boxes is always the product of the denominators." From there, we checked the examples we had done to make sure that was true. Then someone else said, "Oh yeah, it's the same for the numerators, too."
From there, we practiced the procedure for multiplying fractions on the back of the sheet. I had included the methods from the text for the students to refer to when working.
Even with the visual models, some girls were still confused. For those girls, I gave a real world example to anchor their thinking. I said, "If I ordered a pizza that had 8 slices, and I took 2 slices and placed them on my plate, what fraction of the pizza did I take?" The girls quickly answered, "2/8 or 1/4." Next, I said, "I wasn't feeling as hungry as I thought, so I only ate 1 of the 2 slices. How much of my place did I eat? How much of the pizza did I eat? I ate 1/2 of 1/4 of the pizza, which is 1/8." The girls responded well to this example as they could see the fractional part of a fraction more clearly.
Next, the girls completed problems in the textbook, some that required them to use models and some without. I checked the work in each girls' notebook to monitor understanding and re-teach when necessary.
Sample student work:
- Learn how to multiply fractions
- Develop the conceptual understanding behind the procedure
Method:
Using the examples from the Math In Focus: Lesson 4.1, I created a worksheet for the girls to write on to model the concept behind multiplying fractions. I projected the sheet onto the white board and we used different colored markers and highlighters to demonstrate how multiplying fractions is the same as finding a fractional part of the other fraction.
I said, "Which way shows fourths? Color in 1 row to show 1/4. Here there are tally marks to show 1/4. Which way shows thirds? Color in 2 columns to show 2/3. How many units are in the whole rectangle? What fraction is both purple and has tally marks? 2/12 which is the same as 1/6." We followed that same dialogue for the next few examples. After completing a few more, I asked the girls if they noticed anything.
Someone said, "The total number of boxes is always the product of the denominators." From there, we checked the examples we had done to make sure that was true. Then someone else said, "Oh yeah, it's the same for the numerators, too."
From there, we practiced the procedure for multiplying fractions on the back of the sheet. I had included the methods from the text for the students to refer to when working.
Even with the visual models, some girls were still confused. For those girls, I gave a real world example to anchor their thinking. I said, "If I ordered a pizza that had 8 slices, and I took 2 slices and placed them on my plate, what fraction of the pizza did I take?" The girls quickly answered, "2/8 or 1/4." Next, I said, "I wasn't feeling as hungry as I thought, so I only ate 1 of the 2 slices. How much of my place did I eat? How much of the pizza did I eat? I ate 1/2 of 1/4 of the pizza, which is 1/8." The girls responded well to this example as they could see the fractional part of a fraction more clearly.
Next, the girls completed problems in the textbook, some that required them to use models and some without. I checked the work in each girls' notebook to monitor understanding and re-teach when necessary.
Sample student work:
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