## Wednesday, January 29, 2014

### Frosting Equivalent Fractions - Cookie Math

I've been trying to help my younger girls (ages 9 and 7) get a firm grasp on the concept of equivalent fractions.

We've watched videos, colored worksheets, played games, and read fraction themed story books.  But in our house, a lesson never feels complete until the cookies are baked, and in this case - frosted.

So, once again, I found myself rolling out batches of chocolate, and vanilla sugar cookie dough made from our usual recipe.  A (age 12) helped me slice apart drinking glass sized circles of dough, piecing them back together on the baking sheet in pretty alternating patterns of chocolate and vanilla halves, quarters, eighths, sixteenths, and combinations of them all.

Once they were baked, I served up an assortment of the fraction cookies to the younger girls, along with bags of vanilla, chocolate, and strawberry frosting, with instructions to frost half of each of their cookies with vanilla, a quarter with chocolate, and a quarter with strawberry.

They piped on the frosting, making it easier to get where they wanted it, then smoothed it out with butter knives when they were finished.

I left them to complete the project pretty much on their own, so they could work out for themselves how much of each cookie was a half or a quarter.  It wasn't long before I heard them counting out, and very naturally dividing up the chocolate, and vanilla wedges of each cookie in order to frost the appropriate portions.

It was tempting to jump in with a bunch of leading questions - "How many eighths did you have to cover up to make a quarter?" "Did you notice the eighth is half the quarter, and the quarter is half the half?" - and that sort of thing.  The girls were working so comfortably, and so unconsciously with the fractions though, I decided to let the activity stand alone for rumination, that will hopefully lead to an aha! moment on another day.

It's great to be a homeschooler.

Unknown said...

Brilliant! Thank you for sharing.

Unknown said...

Neapolitan fractions- how delightful!

Joyful Learner said...

You just reminded me that I need to cover equivalent fractions! What a fun way to cover them literally! Do you also do disappearing fractions?

Ticia said...

That sure sounds like super yummy math.

Natalie PlanetSmarty said...

I love you sweet math lessons. We are also covering equivalent fractions here, and perhaps I should try some cookies too, at least paper cookies :)