## Reflection: Developing a Conceptual Understanding Crossing Over 100 - Section 2: Teaching the Lesson

Connecting to the reasoning she applies to working with 2 digit numbers helped her when working with 3 digit numbers.

The Common Core standards expect students to count by 10s to 1000, so working with hundreds and correcting misconceptions, is important before students begin to add and subtract with 3 digit numbers.

Correcting Misunderstandings
Developing a Conceptual Understanding: Correcting Misunderstandings

# Crossing Over 100

Unit 6: Everything in Its Place
Lesson 12 of 14

## Big Idea: Students often become confused as they count from one decade to the next. In order to become fluent with operations in addition and subtraction, students need to be able to move across decades.

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Standards:
55 minutes

### Beth McKenna

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