Reflection: Intervention and Extension Delightful Decimals - Section 3: Number Talk with decimals


In retrospect I would have liked to have dedicated an entire lesson to the question of "is it 8.10 or 9?" Even though not all of my students wondered this, there were enough that really didn't relate decimal notation to fractions that I think all would have benefited. As we model Yolanda's strategy and break up the whole and decimal parts: 4+.9+4+.1, I would expect to run into trouble with .9+.1. Relating these to their fraction names and using concrete and visual models like a number line, bar model, cuisenaire rods, fraction circles, etc. help students visualize the resulting 1 whole. Having students do the modeling and the explaining may take longer, but is much more powerful. If they have had to build it, think about, struggle with it, talk about it, make sense of it then the concept has traveled all around in their brains. If they listen and watch then their brains have taken no active role. When students are told they think their job is simply to remember (which is not so simple) and then they miss all the connections in the math.

There is a lot of room in this exploration for extension or remediation. For example they may need to clarify why 8.10 is less than 8.9 or that 10/100 is less than 1/10. 

  Supporting struggling students
  Intervention and Extension: Supporting struggling students
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Delightful Decimals

Unit 1: Order of operations & Number properties
Lesson 9 of 9

Objective: SWBAT apply mental math strategies and properties of addition to decimal addition. SWBAT compare strategies in order to better distinguish the properties of addition.

Big Idea: Students begin to use mental math to gain better decimal number sense.

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