# A Call for Help: My Least Favorite Unit

8September 9, 2012 by ray_emily

My email from the Math Blogging Initiation Team this week exclaimed, “It’s week four. Write a post on whatever you want!”

And so, I want to respond to a prompt that I was a bit nervous about addressing when it was offered up a few weeks back. Today, I want to talk about my *least* favorite unit to teach – my unit on decimal operations.

Although I’m starting to think up some solutions to the problems that I itemize, below, I’ve definitely got a long way to go. I would *love* to know if any other folks have struggled with this unit (or another unit) in the same ways that I am struggling.

Without further ado, here are the reasons why I am less-than-enthralled about teaching sixth graders decimal operation:

- Kids always perform at a variety of ability levels – of course. That we’re not ‘all on the same page’ feels true in an especially pronounced way during this unit, and I’m pretty sure I’m not just imagining it. For instance – some kids solidly mastered decimal operations in fifth grade. Others need to sort out minor confusion, due to lack of practice over the summer. A few kiddos never had a clue.
- Moments of discovery (you know, the moments when class is totally fun and exciting and you love your job the most?) are less frequent, largely because this skill is simply
*not*brand new for anyone. - Kids who decidedly
*don’t*fully understand the skill are convinced that they do, because they’ve seen it before. They zone out, rush through their work, and make lots of careless mistakes. - Kids use a whole bunch of different algorithms, and a wide variety of terminology, which they’ve learned from a handful of different feeder schools. (This is fantastic, but it leaves me feeling stumped – a bit paralyzed, really – when it comes to leading whole-class discussions and working example problems.)
- Algorithms are at the heart of decimal operations. Yes, conceptual understanding is crucial (duh), but let’s face it: When kids are successful at adding, subtracting, multiplying and dividing decimals, they are
*meticulously*following a whole bunch of rules.

In the past, I’ve ended up teaching boring lessons on one or two algorithms, peppering my explanations with lame disclaimers. (For instance: “Yes, you’ve learned this before—we’re just keeping it fresh,” and, “I know you don’t do it this way; that’s just fine. See if you can learn a second method.”) I am not at all happy with this approach. It sucks, basically.

I need to either think up some terrifically amazing way of differentiating (ensuring that all students are suitably challenged), *or* develop some brilliant method of having kids share their knowledge and coach their peers through the process of mastering these skills. Does anyone know of any structures for making this happen? (It’s not just collaboration that I’d want to happen, but rather, one kid would actually teach the skill to another kid.)

*Seriously. What do you do in situations such as these!?*

PS: Worth mentioning: I really struggled to nail down what I wanted to say for each of those bullet points, up there. I felt a sheepishly embarrassed to recognize (mid blog-post, too – eek!) that I’ve clearly spent an insufficient amount of time scrutinizing this situation. Ah well. I wrote the blog post, so up it goes! (I suppose there’s a lesson, there, too…)

PPS: I *was* going to share one recently attempted, halfway decent method of overcoming these struggles, but I think I’ll wait on that and see if y’all have anything better for me. (You’re just DYING of suspense, I bet. Sorry!) Also – I’m still in the middle of this unit; it’s not too late for me to change things up.

Something I started doing when reviewing multiplying decimals (in a bell ringer…made them perform the operation by hand instead of using a calculator OH MY!) is have them estimate (ignoring the decimals) to see if their answer is reasonable. For example, 6.5 x 2.8 = 18.2. Some students struggled with how many decimal places to use. Some students gave the answer 182.0 instead of 18.20. I had them ignore the decimals and multiply 6 x 2…12. Which is closer? 182 or 18.2?

Hope this helps in some fashion.

Thanks! Yes! Definitely planning on getting them to make use of estimation!

[…] call for help was met with one suggestion in the comments, and one suggestion via twitter. Both are lovely ideas […]

In addition to the error analysis work that you’re doing with your kids, I high recommend working with problem strings. A professional developer I’ve worked with for a few years taught me all about them, and she recently published a book called Building Powerful Numeracy for Middle and High School Students. If you go to this link on the Heinemann site you can read a sample chapter of the book to learn more about problem strings:

http://www.heinemann.com/products/E02662.aspx

If you aren’t familiar with problem strings, start reading at the bottom of page 6 in the sample chapter to learn more about them and see examples:

http://www.heinemann.com/shared/onlineresources/E02662/harriswebchapter.pdf

(By the way, I’m not trying to sell her book per se, it’s just the first resource that comes to mind with regards to introducing and teaching about problem strings in depth. I’m sure there are some free resources out on the net. Not to mention that once you get used to them, you can write your own.)

Cool. I am *not* familiar with problem strings, but will most certainly check out the resources you’ve recommended. Thanks!

[…] I wrote about my least favorite unit, as well as my first attempt to improve it. While working with kids on division with decimals, […]

This is my second year teaching (math only now for 5th and 6th grade) and I have a bunch of boys that love anything and everything to do with the military. Because we needed a quick review of decimals we had Decimal Bootcamp. With the “bootcamp” mentality they came to call willing to work hard. We even had “graduation” at the end of our two weeks with diplomas and music! They loved it and have even asked if we are having any other bootcamps!

This year I did something totally different with decimals. I parsed out my decimals unit with my fractions unit. So, there was a big unit on addition and subtraction of fractions AND decimals. Then, there was a big unit on multiplying and dividing with (again) fractions AND decimals. The idea was to get kids to notice parallels and not think of fractions and decimals as these things that exist in isolation and have no relation to one another. Overall, I’m really pleased with the change.