## Finding the Difference

My second grade math group started this week.  I gave a pre-test on Monday and found that students had some trouble with the word difference.  Many of the second graders saw the word difference and immediately thought subtraction. I could see why students would see this as a quick search reveals difference as being “The result of subtracting one number from another” and “How much one number differs from another.”  I think most students in my class focused on the first definition rather than the latter.  While discussing the word more than a few students brought up that they knew how to find the difference using a method.  It ended up being the standard subtraction algorithm.

On  Wednesday students were introduced to part of a 100 grid and asked to use it to find the difference between two numbers.  Some of the students started to see that difference could be interpreted as distance between.

Students used two different colors to locate and identify the numbers.  Students then counted the space between the two numbers.  They used hops while moving to the right and then down.

Another student used the grid to show a different way to find the difference.

I showed both methods under the document camera and the class discussed how both could work.  Students were then asked to place their strategy on a number line.

Another student raised their hand and wanted to show the class something that they created.

Next week the class will be investigating regrouping strategies.

## Educanon and Formative Assessments

The second grade classrooms at my school reviewed subtraction strategies last week. Students were subtracting numbers on a number line and becoming more confident in using regrouping strategies. Based on pre-assessment results I felt like some of the students would benefit from additional enrichment. While talking with a few colleagues I revisited Educanon. I first heard of Educanon from Mary and I briefly used it last year. So I dusted off my username and password and logged into my account again.

A while back I created a subtraction video using Explain Everything. I turned off the microphone function (my dog was barking when I created this) and just used the pointer and drawing functions. The video was only around two minutes in length, but had 10 questions. I added a variety of questions, including multiple choice, fill in the blank and checklists. The last question asked the students to use a whiteboard to find the difference between two numbers.

During class students were placed in two different stations. One station was Educanon and the other was working with base-ten blocks to subtract multidigit numbers. The stations rotated after approximately 10-15 minutes. All students logged in and finished the Educanon within the time period.

After class I was able to review the results. I felt like this data could be helpful for the teacher as well as the student.

The next day I printed out the student results and compiled a reflection sheet.

Each student’s answers were stapled to the back of the reflection sheet. As a class we reviewed each question together and students filled out their specific sheet. Out of all the categories on the sheet, I thought the “Key Vocabulary/Concept” section stood out. Students started to develop an understanding of what type of skills were being addressed from each question. This was also an opportunity to emphasize certain math vocabulary words. At the end of this reflection session, students circled their effort level on this formative assessment.

I thought this was a beneficial activity for a second grade classroom. Students are also starting to think more about their own mathematical thinking and learning. I’ll be using the data and student reflection in preparation for more challenging subtraction concepts later in the year.