Saturday, December 22, 2012

Clothespin Fractions

Order and compare fractions on a number line with these simple materials from the Dollar Store.

Materials Needed:
clothespins (pack of 36 for $1)

1. Use a fine Sharpie to label clothespins with the fractions you wish to explore.
2. Place clothespins in a Math Station or Workbox, along with a hanger.
3. Ask kids to clip the clothespins to the hanger--the "number line"--in order. Differentiate with varying numbers of clothespins. Change the range of the number line by removing larger or smaller numbers. For example, the number line could include clothespins from 0-1 or from 0-1/2. When students find equivalent fractions, they may clip them to fractions of the same value in a vertical line.

Additional Option: You could number or letter the back of the clothespins so that students could check their own work. (Label a set from A-Z, for example.)

Clothespin Fractions provide a powerful model for discussion. My ten-year-old son, an eager test subject, jumped right in to order the clothespins. His dad checked answers. I wish I'd recorded the ensuing dialogue. My husband, a guy with a ton of math smarts, tried to figure out the answers using percents. Since this is something he regularly uses at work to create documents, he felt like it was an efficient method. In contrast, I relied on common denominators. My husband helped my son to make a couple order changes but finally admitted that in one case, my son's original answer was actually correct. (Talk about making a kid's day!) We then talked about how my method was easier the merits of using percents vs. common denominators. I felt a fraction wee bit smug. 

But more importantly, we all had a fun, productive Math Talk!

Want more ideas for teaching fractions? (One of my favorite topics to teach!) Click here! :)
CCSS Standards in Grades 3-4: 
CCSS.3.NF.A.3a Understand two fractions as equivalent (equal) if they are the same size, or the same point on a number line.
CCSS.3.NF.A.3b Recognize and generate simple equivalent fractions, e.g., 1/2 = 2/4, 4/6 = 2/3). Explain why the fractions are equivalent, e.g., by using a visual fraction model.
CCSS.4.NF.A.1 Explain why a fraction a/b is equivalent to a fraction (n × a)/(n × b) by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions.
CCSS.4.NF.A.2 Compare two fractions with different numerators and different denominators, e.g., by creating common denominators or numerators, or by comparing to a benchmark fraction such as 1/2.


  1. Super idea! Will definitely try this in the new year!

  2. I appreciate that you offer this simple, yet effective idea without charge. Thanks.


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