Using Unifix® Cubes to Support the Development of Number Sense

By Neily Boyd
Nov 20, 2019

A lack of number sense is frequently the reason given when a student is struggling with math. But what do we really mean when we say “number sense” and why are so many students struggling with it?

A common definition of number sense comes from the Van de Walle publication, Teaching Number Sense: “Number sense is a good intuition about numbers and their relationships. It develops gradually as a result of exploring numbers, visualizing them in a variety of contexts, and relating them in ways that are not limited by traditional algorithms.” (Van de Walle, 125)

A lack of number sense occurs when students don’t have enough opportunities to explore the relationships between numbers. One way to support early number sense is through activities that build an understanding of one more/one less and two more/two less.

How does this aid in the development of number sense? “When children count, they don’t automatically think about how one number is related to another. Their goal is only to match number words with objects until they reach the end of the count.” (Van de Walle, 126)

Unifix Cubes are the perfect tool for visualizing one more/one less and two more/two less. Here are two fun ways to practice:

Unifix Cubes Counting Tower

1) One More/One Less Towers: Count out and build towers that get bigger by one more each time. This allows children to visually and concretely understand that each number in the counting sequence means I have one more than the last number I said. Doing the process in reverse is also valuable. By making a tower of one less each time, children see that when we count backwards, each number is one less than the number before.

2) One More/One Less Machine: Send a stick of Unifix Cubes through this home-made “machine” and talk about how many cubes are on the stick now after the machine adds one more or one less. You can make this "machine" using a cardboard box, cut the ends off either side and wrap construction paper around it. In this example you, or your students, can send their stick of 5 Unifix Cubes through the one less machine. While in the machine, be sure to pop off one cube. The stick comes out with one less - 4! After your students have had plenty of practice with one more and one less, make the machine a two more/two less machine. Unifix Cubes One More One Less Moving to the idea of two more/two less helps your child start to realize that 6 is one more than 5 but 2 more than 4. This continues to deepen their understanding of how numbers are connected.