## Where’s the Math?

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August 02nd, 2017Students’ ideas often amaze me, and Lydia’s is one of the most suprising examples. She used 7 x 3 = 21 to figure out that 8 x 4 = 32. She reasoned that since the factors in 7 x 3 were each 1 less than the factors in 8 x 4, she’d just increase each digit in the answer, changing 21 to 32. She was correct! Read about Lydia’s discovery, what I did, and what I learned.

## Post from Marilyn’s Blog: The 1–10 Card Investigation

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June 03rd, 2016The 1-10 Card Investigation has a big payoff with students. It engages their interest, involves them with making sense of a problem and persevering to solve it, and gives them experience with evaluating their progress and changing course as necessary. Plus it has a playful aspect that too often is lost in math class.

## Post from Marilyn’s Blog: A Problem with a Word Problem

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May 13th, 2016A word problem on a third-grade standardized math test didn’t call for a numerical answer, but instead asked students to decide if the problem should be solved by adding, subtracting, multiplying, or dividing. One third grader complained to his teacher, frustrated because he thought there was more than one correct possibility.

## Post from Marilyn’s Blog: Word Problems

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March 30th, 2016Word problems have long been difficult and frustrating for students to solve and for teachers to teach. A colleague recently forwarded an email from a woman looking for resources to help her fourth-grade granddaughter with word problems. I thought for several days about how to offer positive support to both the grandmother and her granddaughter.

## Post from Marilyn’s Blog: The Game of 2048

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March 02nd, 2016Several months ago I received an email message from my friend Sandra. She wrote, “If you want something new to distract you, try playing the new game 2048. I’m finding it addicting.” I took Sandra’s advice and downloaded the free app. And, like Sandra, I found it addicting. But it also led me to think more about what I think is important when we teach math.

## Post from Marilyn’s Blog: Word Problems: Don’t Put the Cart Before the Horse

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February 03rd, 2016A long-standing instructional practice has been to teach students how to multiply (or add, subtract, or divide) and then, after the students have learned to compute, give them word problems to solve. In this post I present a lesson with a different approach, where word problems become the lead and reason for learning to compute.

## Post from Marilyn’s Blog: We Ask, We Listen, We Learn

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October 23rd, 2015How much is 12.6 × 10? This is a question from the Math Reasoning Inventory (MRI) decimal assessment. What do you think were the most common incorrect answers given by the more than 7,800 students who figured out the answer in their heads? And what about the boy who answered, “One hundred twenty and thirty-fifths?”

## Post from Marilyn’s Blog: A Mental Math Lesson

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July 15th, 2015I taught this mental math lesson to a class of fourth graders. I chose an addition problem—99 + 17—for the students to solve mentally, purposely selecting a problem that would be accessible to the students. Also, I knew that the problem could be solved in different ways. I planned to elicit from the students strategies for figuring out the sum of 116 and then to show video clips of other students solving the same problem. After watching each video clip, we’d analyze how the student reasoned and then check back to see if anyone in our class used the same strategy.