## Grade 2 & Grade 3 Two digit number

**Number Sense for 2 and 3 digit number is no different than number sense for number to 10. **

**Identify the quantity & Express multiple ways using place value units**

**words, multiplication units, expanded expressions, expander cards, blocks to 100 grids to number lines. STOP the pictures of tallies and circles. Build imagery that links to number so that students can use expressions. ****ADDITIVE COMPOSITION focus only on parts inside the whole to begin.**

**Equal**

*record expressions and connect expressions multiple ways Associative & Commutative Properties emerge*

**Magnitude & Density**

How close to? How far away from? Relate to other numbers. Use referents of decades, (multiples of 5 & 10) , 50 and 100 and the language of more than, less than, between, near, about. Stretch area models into number lines. **COMPARE **

**Inverses**

*understand the relationship and how to record it using the addition and the subtraction signs. Missing parts can be explained when you have solid number sense. Relate using the grid and explaining the space. Relate using the number line and explaining the distances between.*

**Build 2 & 3 digit with your students using the BERCS DECKS listed below.**

The Two Digit Number and Three Digit Number books contain blackline masters and support pages that help you develop individual and whole class practice routines. They are ordered separately. ** Just list what you want in an email to glorway@thinking101.ca. **

** Decks are in colour and laminated. Your cost $12 per deck. The Two Digit Book is $39.99 and the Three Digit Book is $29.99. I accept Visa, e transfer and school PO or personal cheques. **

**Get in the habit of building lists of expressions as students explain what they see, then encourage students to look for patterns in the lists so they are focused on organizing data.**

The page below is meant to provide you guidance as you work with 2 digit number. There are several more pages of explanation here. HUNDRED GRID Hand out April 2018 .

It is part of a booklet of materials I am developing. Please respect my copyright and do not reproduce for others.. Thanks.

Download the sheet above here.

## NUMBER LINES MATTER

I move students between area models (grids) and number lines. The goal is to support them as they develop mental capacity for manipulating and managing number compositions in their mind’s eye. In other words, the goal is to move away from drawing and writing and toward efficiently expressing your thinking on paper. If you can add, use it to subtract. All you really need paper for is to make sure you do not lose track.

The number line is not magic nor is it worthy of special marks. It is a tool for developing a robust sense of number and accuracy with computations.

## The samples below are Grade 2 thinkers as they solve problems that involve two digit numbers. This thinking has developed from understanding the imagery of the grid.