### Why I'm Not Teaching Decimal Operations "Rules"

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1. Good idea, Ellie.the, "I tried my best..." explanation always kills me. (Sorry, not trying to advertise but I don't know how to give this to you any other way.) If you'd like, stop over at my store (Pamela Kranz) and grab my free Become a Math Lawyer, Defend Your Answer poster/label set. It broke my 6th graders of the I-don't-know-but-it-looks-right routine. :) Good luck!

2. Thanks, Pam, I'll check it out!

3. My students always mix up the rules with decimals/fractions/integers operations. It is important to teach them the reasons why instead of just the rules. Like you said, they need number sense. When you add decimals, you are adding place values. When you multiply 2.7 x 2.4, you are making 2.7 groups of 2.4 and estimating helps determine your answer.

Interesting way to put this! I've got a year to rethink my decimal operations unit.

### Memory Wheels - First Day, Last Day, and Any Day in Between!

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### Math Class - First Day Activity

Rectangle of pentominoes Many 6th graders seem to have a pretty negative attitude about math, so I try to do something interesting to "grab" them during our first class. Last year, during the first math class, we spent part of the period working with pentominoes. Before working with the pentominoes, however, we played a name game so we could learn each others' names (I find it impossible to start anything else if I don't know some names, and fortunately, I learn them fairly quickly). rectangle outline For the activity, I divided the students into groups of 3 or 4. The directions for the activity were not complicated - the task was to make a rectangle, using all of the pentominoes. I gave students an outline of the rectangle, as pictured to the left, so they would know the correct size of the rectangle. The squares in the grid are each one inch. The rectangle is 5 squares (inches) wide and 13 inches long (13 inches includes the row that has the "Pent

### Ratios Fold it Up!

Getting started with ratios! We pretested ratios, rates, and proportions last week, and I found mixed results in the item analysis. I was surprised to find that very few students were able to write a ratio (the pretest question was: there are 2 hamsters and 1 gerbil - write a ratio of gerbils to hamsters). It wasn't that they wrote the ratio as hamsters to gerbils rather than gerbils to hamsters....they either left it blank, or wrote something that did not resemble a ratio. So, I was glad that I had prepared a couple of Fold it Ups for them to use this week! I think this is the first time I've used this version of Fold it Up (with the triangles folded in) this year, and a few students commented that they like this version better than others (like the one I made for Wed...bummer), because this type won't rip as easily. Click to download...a pic of the inside is in the document. Do you have any favorite ratio activities? Subscribe to Middle School Ma