# Equal Matters

## ASSESSING NUMBER SENSE: Equal Matters

Understanding the concept of equal and the role of the equal sign is one of the 4 foundational pillars upon which  number sense builds.   If our goal is to see students develop and master fluent, accurate and efficient strategies for solving addition and subtraction equations, we must include tasks that attend to developing a rich and robust understanding of what it means to be equal in math.

### When I heard him explain I saw this in my mind

To understand the inverse I can move forward or back between the 2 numbers. If I shift everything to the right I have constant difference. My purple arrows show that. Here is what I thought when he said it was all about difference.  Can students understand the connection between his explanation and my number line?

### How do you know?

Constant difference thinking relates to this type of ‘logic’ problem.

And these problems relate to what are classified as ‘systems of equations’ problems in high school and beyond.