My classes have been recently exploring fraction division. Students completed word problems involving dividing fractional pieces and they were finding the idea challenging. In order to gain clarity, I worked with students in small groups to determine where the trouble spots seemed to developed. I started to notice a couple things: 1) students were relying on a fraction division algorithm without context 2) students were not sure how to determine the dividend, which made creating a number model problematic.
Relying on the traditional fraction division shortcut ended up causing problems for more than a few of my students. Students were not able to explain their reasoning for flipping the second fraction. This become even more apparent when students attempted fraction division word problems. Because you have to “flip” the second fraction students were not sure how to identify the dividend. This caused confusion. I planned out a small fraction bootcamp for students to explore fraction division through visual models. Students started out with problems like 2 ÷ 1/4 and progressed to where a fraction is in the divisor and dividend. Students were making progress and relying less on the shortcut method, although some used that to check their work.
After our mini camp, students were given prompts to show their understanding of fraction division.
1.) Juliane has 12 bags of confetti to spread on 16 tables. She wants to put the same amount of confetti on each table. How much of one bag of confetti should she put on each table?
This was the first problem and achieved the highest accuracy. Students drew out the 12 bags and spread it on 16 tables, finding the answer to be 12/16. Some showed a number model of 12 ÷ 16 = 12/16 and others drew a picture.
2.) Write a number story that can be modeled by 4 ÷ 5 = 4/5
This was more challenging. The number stories indicated whether a students could determine what was being shared and in how many pieces. It was interesting to read the responses and revealed an understanding of what is being split equally. Here are a few response:
There were 4 candy bars and 5 children. How much of the candy bars will each child get?
I have 4 boxes of apples and I wanted to put them in 5 bags and all the bags have the same amount of apples. How much of the box of apple go into the bags?
Tyler has 4 rats and 5 carrots for his rats to each get equally fed how much will each rat get?
There were 4 oranges jamal and his four friends wanted to spilt the oranges to a even amount how much of and orange does each person get?
3. Explain using words and the process you would use to complete the problem 5 ÷ 1/3. Give the reason why you completed each step.
This problem caused a few student headaches – but in a good way. Students that relied on the shortcut were confused in how to explain the reasoning for flipping the second fractions. Out of all of the problems, this one highlighted the conceptual understanding of fraction division the most. Some students sent in pictures with written explanations while others created number models. Here are a few of the responses:
First I would do 5 ÷ 1/3 This works, because it is the same question just written in a different way. Next I would see how many 1/3 can fit in 5. To do this I would do 5*3. This works, because there is 3 1/3’s I one. And there is 5 ones in 5*3 = 15. So the answer is 15. (appreciate the thorough thinking behind this response!)
First I switched 5 to 5/1 and then 5/1 to 15/3. Why I did this is to make the denominators the same same number. Then I divided across numerators and denominators to get 15/1 then I simplified 15/1 to get 15. Why I divided across numerators and denominators is to get the answer. Why I simplified to make the number a whole number.
I think the answer is 15 because you can think about how many 1/3 are in 5 and that answer is the answer to your problem.
First I converted 5 to 5/1 then I did 5/1 divided by 1/3 to get 5/1/3 then I did 5/1/3 X 3/3 to get 15/1 which I simplified into 15
I was pleasantly surprised to see the improvement in being able to navigate fraction division. Being able to conceptually understand fraction multiplication/division can sometimes be a roadblock for students. I am hoping to break that and looking forward to discussing and highlighting a few student examples with the class next week.