Idėjų kampelis: liepos 2014

2014 m. liepos 23 d., trečiadienis

Trupmenos. http://artistryofeducation.blogspot.com/2014/07/the-magnified-inch-for-fractions.html

The Magnified Inch for Fractions

I heard about the Magnified Inch lesson from a colleague about ten years ago and then read about it in a book called Family Math. The authors put this lesson in the measurement category, but I find it helpful when teaching fractions. Here is my version of the lesson:

I start by cutting an eighteen inch strip of construction paper for each student. ( I always make extras.) I have students fold the ends together to make half. I label it with a fairly long line, but I leave enough room to show equivalent fractions.

Next, I have the students fold each end to the center. We talk about cutting each half into half. I label each part with a slightly shorter line like you would see on a ruler and mark the lines 1/4 and 3/4 respectively. I tell them that 2/4 is the same thing as 1/2 and write in that label as well.

The next part is where I lose some students. I need to fold each fourth into half. I have found that the simplest way to do this is to fold each end of the strip to the 1/4 mark and then to the 3/4 mark. I label the new marks 1/8, 3/8, 5/8 and 7/8. I explain that 2/8 = 1/4, 4/8= 2/4=1/2, and 6/8 = 3/4. Decide how much guidance your students need with labeling equivalent fractions based on how much experience they have had.

I use this tool as a number line. We talk about which fractions are greater or less than others. I let them use it as a tool as we go through the unit. I find that because my students have created this tool, they understand it better than a number line printed in a book.