I started the week with a little math review - just a few questions looking at some of the skills and concepts we have been working on. I do this every few weeks just to keep students connected to the math (ie. we don't just "do" fractions for 2 weeks and then move on) and to give me a little snapshot about how the students are doing. I can quickly see where we might need to spend some more time or if I might need to do some direct re-teaching of things. For questions involving operations, I often ask the students to show how they figured it out (strategy use) or I ask them as I am circulating and marking their reviews which is what I did this time. These little mini math interviews give me great insight. I have several students who are able to compute two-digit addition questions in their head but are still unable to explain how they did it. Some of this is a language issue and some of this is because they have been doing this kind of math long before I entered their lives and are kind of stuck in the way that they learned how to do it.

On Tuesday, we played a little complement number game where students had to find complementary numbers (numbers that go together) for 50. Students need to know their facts for 10 (8 and 2, 6 and 4, etc) really well for this. Doing this made me realize we need to work on adding tens so I pulled out my big ten frame cards. We worked on 9+ and 8+ strategies using the cards and then we transfered this thinking to 90+ and 80+.

On Wednesday, the teacher whose classroom I teach math and science in, was celebrating 100 day. I read the students the story, The Very Rich Kind Lady and her One Hundred Dogs. The students loved all the dogs names! As we read the story, I stopped at the end of each double-page spread of dogs and asked., "If we've met 31 of the dogs, how many more dogs do we need to meet?" This got at complementary numbers for 100 and a few students realized this right away and made the connection to the game we did for 50 the day before.

At the end of the story, I posed a problem for the students to solve and then asked them to create their own problems. We've done this a few other times this year, and the students are still generally modeling their problems on ones I have posed to them.

On Thursday, to continue with thinking about complementary numbers, decomposition and adding strategies, I gave each table group a 30-sided die and asked each student to roll once and for them all to record the sequence of numbers rolled and add them up mentally. Simple game that involved lots of mental math and the students were so excited to use the 30-sided die, there was lots of engagement. Some of the students discovered how to make the dice spin like tops! As I circulated as they were playing, I listened in on students explaining how they were adding their numbers up. I had some of them share their approaches and recorded these on a chart for all to see.

We also have been going over subtraction strategies for subtracting two-digit numbers. I had the students choose the numbers and then modeled the open number line approach for them like we had used for adding. I think it's important that students understand that subtraction can mean "taking away" but it also means "finding the difference" and the open number line really highlights this.

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