Engaging students: Determining the largest fraction

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission again comes from my former student Perla Perez. Her topic, from Pre-Algebra: determining which of two fractions is largest if the denominators are unequal.

What interesting (i.e., uncontrived) word problems using this topic can your students do now? (You may find resources such as http://www.spacemath.nasa.gov to be very helpful in this regard; feel free to suggest others.)

 

Students are introduced to fractions in elementary school, but at a certain point this topic can become tedious. Trying to introduce new concepts to a topic they’ve seen and practiced for a while can be a challenge. A good idea can be to give them a problem at the start of class that they can answer after the day’s lesson is done. Students are given a word problem such as:

“James was arguing with John that he could eat more pizza than him, while John without a doubt believed the opposite. It got to the point where everyone in class had established their own opinions on it. So Nancy came up with a solution and ordered two large pizzas to see who could eat the most. Well, when the pizzas arrived they noticed that one pizza was cut into 10 equal pieces and the other into 16 equal pieces. After they devoured all that they could, John had eaten 7/10 and James had eaten 13/16. Now, who at the most pizza?”

After giving the students to time to think about the problem without any more information, get a show of hands to see who they think ate the most. Write up the number of students who voted for James and John somewhere visible. Then, at the end of the lesson, give and explain the answer.

 

 

How has this topic appeared in the news?

 

The euro currently cost .890646 or 445323/500000 of a dollar. The British Pound .753423 or 753423/1000000 of a dollar. Now which currency is cheaper? If the fraction were only given to a student, some might be able to say the British pound because the 7 is greater that the 8 while others might say euro because of the 5 in denominator, and some that have no idea. There’s actually a formula to find out which is: AMOUNTto=(AMOUNTfrom X RATE from)/RATEto Although most times currency exchange is shown in decimal form, it gives a broader sense of how a simple concept relates to big-world topics. It is important for students to be able to determine if 3/7 is greater or less than 4/5, so that one day they can apply it to their daily lives. The exchange rate is just one example of different fractions being used in today’s society; in this case how the use of decimals and fractions translate to foreign relations. By relating the outside world to a classroom, educators can show students that there is more to numbers than just a grade in a class. These real world concepts can help students better understand the application of the material.

References:

http://www.mathinary.com/currency_conversion.jsp

http://www.x-rates.com/table/?from=USD&amount=1

 

What interesting things can you say about the people who contributed to the discovery and/or the development of this topic? (You might want to consult Math Through The Ages.)

 

To students it may seem as if fractions have always been there. Some may have not thought much of its origin. A brief interesting part of history can be shared to spark some light in the matter. Well although there were contributions from the Babylonians, Arabs, and Ancient Rome, it was the Egyptians in 1800 BC seem to be the ones already using them. But interesting enough it isn’t like how it is seen today. Rather than seeing a fraction be an integer over another they used hieroglyphics and base ten.

For example, “The Egyptians wrote all their fractions using what we call unit 1 as its numerator (top number). They put a mouth picture (which meant part) above a number to make it into a unit fraction.”

It would be represented like,

Because of this method it was difficult to compute so they had to use numerous tables. Although our methods have changed one thing still remains the same; the way we use manipulatives in showing how fractions with different denominators compare. For instance, we have circle pictures that visually show fractions with different denominators can ease student into understanding them better.

Babylonians, though found a simpler way of representing fractious with symbols. All in all, it is interesting how visual description can be helpful still in today’s society.

 

References:

https://nrich.maths.org/2515