## Reflection: Rigor Taking Apart the Problem - Section 1: Warm Up

When I looked back at the results of the 3 minute fact check and thought about what I had witnessed as students worked, I was impressed that all students were able to complete the addition. What I did notice that was disappointing was how much more difficult the subtraction was. With addition I saw many students respond to the problems without counting, or number lines or fingers.

They showed the automaticity with the early facts that the Common Core Standards extends in grade two to numbers to 20. With subtraction there was little automaticity. Students had strategies for figuring out the subtraction. They relied on their fingers, number lines or number grids to find the answers. While relying on the math tools is acceptable at this point in the year, I want students to move away from having to figure everything out, to more automaticity with the subtraction facts. One skill critical to success in subtraction is to be able to count backwards, starting with any number, as fluently as they count up. Students do not get enough practice with counting backwards. Whenever possible, count backwards for and with students, rather than forward. If you are giving the students 20 seconds to clean up, count backwards rather than forwards. Encourage them to join it.

It is important for students to develop subtraction automaticity, because as numbers get larger the cognitive demand increases, but they will be spending that energy and time on the simple computation that should only take a few seconds. (I have tutored a 6th grader who never developed this automaticity and she counted on her fingers for every problem she needed to solve. She became overwhelmed by the task and it was necessary to go back and relearn these second grade skills.)

Developmentally students can understand when things get smaller, but addition makes more sense. As a teacher, I need to continue to develop their understanding of what subtraction is, and how it is a reverse operation of addition, but not something to be afraid of.

# Taking Apart the Problem

Unit 2: Adding and Subtracting the Basics
Lesson 6 of 18

## Big Idea: The Common Core standards encourage students to solve problems by being able to take problems apart and determining important information.

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55 minutes

### Beth McKenna

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