# Grade 2 & 3 Two digit number build

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.

## Introduce the 100 grid #1 August 15 2018

I use this image to address misconceptions. Four on its own is misleading. Four ones is the place value notation. One fours is multiplication but not place value.

My dot collection materials include a variety of independent practice pages. Two Digit Number book in pdf is available by email: glorway@thinking101.ca \$35

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.

## NUMBER LINES MATTER

Here are 2 powerpoints for thinking about how to stretch number from an area model to a number line model. Two Digit number line intro 2019

Talk through 2 Digit 2018