Today we used factor trees to help us simplify fractions. We used a worksheet titled "Wacky Graphs" from The Mailbox Magazine (Intermediate-Dec/Jan 2000-01- p. 29). This page required the students to (1) read the problem (2) determine the fractions they are to use, (3) simplify the fraction, and (4) match their fractions to the appropriate graph.
I like this page because the fractions are not immediately apparent. The student must determine the denominator, then each set of numerators. Sometimes all of the numerators are named within the problem, but sometimes students have to use number sense to determine the missing numerator.
I wanted the classes to use factor trees to simplify their fractions because they will be more likely to use a factor tree than finding all of the factors of the numbers they are faced with. My other concern is that when making a list of factors using a t-chart, many of my students will miss a factor. Many times the factor they miss will be the factor they need!
After working the first three problems together (follow the link to see our work), I asked the kids to work as table groups to put their new knowledge to the test. I want them working together so that I can hear their thinking and help if I hear any questions, concerns, or misconceptions.
Before leaving the room, the students were asked to complete an exit ticket. The prompt was:
Explain how to find the simplest form of 24/36.
I wanted to not only see the use of a factor tree, but I also wanted to read an explanation of how to use the factor tree to simplify the fraction.
HOMEWORK: finish Wacky Graphs