Using Cuisenaire Rods for Fractions

This is a math series follows our unit for introduction to fractions in grade 3.  This is one of several. Look for the others by searching “fractions.”  This post contains affiliate links.

Day 10

It’s was our first day from spring break, so we started out homeschooling slow with only two tasks: nature study and main lesson (fractions.)  This was our first day with the rods.  Though Gattegno goes through fractions in his textbook, I find  The Handbook of Activities for the Teaching of Mathematics at the Elementary School’s activities are more useful and practical.  The Handbook is developed by and based on Gattegno’s work and is published by Bronx Charter School for Better Learning.  You can find that publication for free HERE.  I also wanted an easy way to get the rod work that we did into her notebook. After thinking through for a while, I decided that a stamp pad set was the easiest way of doing this, so I researched to find a good set that matched the color of our rods.  You can find the stamp pads HERE and the Cuisenaire rods we are using HERE. (Here are more of my math resources.) We reserved one  of each rod to use only for stamping.  This turned out to work beautifully.

The first day of rods, we did the activity found on Section I A3(b) #2 “Introduction of Fractions.”  We started out with 2 white blocks and 1 red blocks.  We talked about how the red was twice as long as the white, and that made the white how much? ½ of the red.  This came pretty easily to her, so we moved on to using other blocks such as the red and purple, light green and dark green to show halves.  Then we stamped these examples into her notebook.  From here we went on to look at thirds.  We used a light green rod and three white rods talking about how the green was three times as long as the white. That meant the white was 1/3 of the green.  We then used several other rods to show thirds, and then used this same process to show fourths.

homeschool-4

Day 11

Today we moved on to working with fractions that did not evenly fit into each other, for example we used a light green (3) and a black (7.)  Since three did not fit easily into the 7, the fraction was more difficult to determine.  Here I introduced the white rod.  We noticed that white divides evenly into the black rod 7 times.  That makes a white rod 1/7 of black.  If 1 white is 1/7, then 2 white rods is 2/7, and 3 white rods are 3/7. Since 3 white rods are equal to a light green, then the light green is also 3/7.  We then determined the red rod to be 2/7, the purple to be 4/7, the yellow to be 5/7, and the dark green to be 6/7.

From this point we move on to working with the dark green rod and sixths. I could tell that this was too much for her, and she couldn’t make the leap.  I will try a different approach tomorrow, maybe replicating the process that we did for the number line and circles with the rods.

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