Today for fun, we repeated an activity Bruce and I had done a while ago, called Peanut Buttering fractions. This is a lesson on reducing fractions that I learned with I was going through teacher training for Constructivist math. It is a wonderful example of a hands-on activity helping children construct their own understanding of a mathematical concept. The whole word “reducing” doesn’t make a lot of sense when you think about it, because the actual quantity of the fraction your reduce never decreases or diminishes. Peanut buttering, makes a lot more sense.
To start, I asked Bruce to tell me which fraction of the MnMs were red. He answered 3/9.
By this point, Bruce totally remembered what to do next, which was the reduce the fraction with peanut butter. But with a child new to the activity, there is a lot language prompting you can introduce to help guide them to discovering how this works on their own. “Look for groups. Do you see a way to group the candy evenly? Instead of having so many red candy, can you make a clump with peanut butter? Oh, you make a red clump of three, can you make green clumps of three?” etc.
After peanut buttering, 3/9 of the candy being red, becomes 1/3 of the candy.
Here’s another problem we did. By this time, things were getting pretty sticky!
What fraction of the candy is green? 10/20
Bruce’s first attempt at peanut buttering, and he turned 10/20 into 2/4.
I asked him to if he could peanut butter even more, and he made 2/4 into 1/2. 1/2 of the MnMs were green.
On a side note, my MIL brought that giant tub of Jif over to our house when my husband and I were in Europe. We usually eat organic peanut butter instead. The hydrogenated stuff actually works better for this activity though, because natural peanut butter is a bit too slippery.