In this video, we introduce the idea of subtracting integers by using simple subtraction of a positive by a positive (black squares) and negative...

# Category - Number Sense

Last time, we added positive and negative integers using black and red squares. Now we will show the red squares first and students see that the...

Adding and subtracting integers can be a challenge for many students. When students struggle with this idea, we often resort to memory tricks...

Consider using these images to prompt number talks around conceptual subitizing and unitizing as we push students thinking from additive to...

This dot card image was shared by Jo Boaler at a recent workshop. Because there are more than 5 dots, most people will conceptually subitize by...

As you saw in the Subitizing and Unitizing videos, these Counting Principles are mighty important. Consider using these images to prompt number talks...

Unitizing is the understanding that you can count a large group of items by counting smaller, equal groups of items from within the large group.

Movement is Magnitude is the counting and quantity principle that refers to the understanding that as you move up the counting sequence (or...

Hierarchical Inclusion is the counting and quantity principle that refers to understanding that all numbers preceding a number can be or are...

In general, subitizing is the ability to “see” or visualize a small amount of objects and know how many there are without counting. While this idea...