Number Sense Unlocked: The Power of Unitizing and Problem-Solving

In the previous posts of our series on number sense, we explored several key components that contribute to a comprehensive understanding of numbers. We covered subitizing, which is the ability to instantly recognize and understand small quantities without counting. Magnitude was discussed as the understanding of relative quantity and size. Counting, one-to-one correspondence, and cardinality were emphasized as foundational skills that establish order, ensure accurate counting, and determine the total quantity of a set.

We also explored hierarchical inclusion, which involves recognizing the grouping of numbers into subsets within larger sets, and part-part-whole relationships, which involve decomposing and combining numbers to form new quantities. Additionally, we discussed compensation as the skill to adjust numbers to simplify mental calculations while maintaining their overall value.

In the upcoming third post, we will address the final components of number sense, completing our exploration of this essential concept. We will delve into the topics of problem-solving in conjunction with subitizing, magnitude, counting, one-to-one correspondence, cardinality, hierarchical inclusion, part-part-whole relationships, and compensation.

We will examine how these components interplay and contribute to effective problem-solving strategies, empowering individuals to apply their numerical understanding in practical and real-world contexts. Developing a strong number sense is not only vital for mathematical proficiency but also for enhancing critical thinking, logical reasoning, and problem-solving skills. By continuing to explore the remaining components of number sense, you will further deepen your numerical understanding and become better equipped to tackle various mathematical challenges.


Unitizing refers to the ability to recognize and work with numbers as single units or groups rather than individual counting elements. It involves grouping numbers together and treating them as a single entity or unit, enabling individuals to work with larger quantities efficiently. Unitizing builds upon counting skills and the understanding of quantity by allowing individuals to work with numbers more fluently and flexibly.

Strategies and activities that foster the development of unitizing skills include:

1. Skip Counting: Encourage individuals to practice skip counting, which involves counting by a specific increment or unit. For example, counting by twos (2, 4, 6, 8, etc.), counting by fives (5, 10, 15, 20, etc.), or counting by tens (10, 20, 30, 40, etc.). Skip counting helps individuals recognize patterns and see groups of numbers as single units, enhancing their ability to unitize. You can easily arrange your counting collections to be for skip counting. Read more about counting collections here.

2. Recognizing Multiplication Patterns: Explore multiplication patterns with individuals, highlighting how multiplication involves repeated addition and the grouping of numbers. For instance, show how 3 × 4 can be understood as three groups of four, emphasizing the concept of unitizing the four as a single group. This helps individuals see multiplication as a form of unitizing and reinforces the idea of working with numbers as units or groups.

3. Visual Representations: Utilize visual representations such as arrays, grouping models, or number lines to reinforce the concept of unitizing. For example, when representing multiplication problems, use arrays to demonstrate the grouping of numbers into rows and columns, helping individuals visualize the unitizing process.

4. Relate to Real-Life Scenarios: Connect unitizing to real-life examples and situations. For instance, when measuring ingredients for a recipe, discuss how unitizing is employed when using cups or tablespoons as standardized units of measurement. By highlighting such examples, individuals can better understand the practical applications of unitizing in everyday life.

5. Problem-Solving Activities: Engage individuals in problem-solving activities that require them to identify and work with numbers as units or groups. This can involve tasks like solving multi-step word problems, breaking down complex problems into manageable parts, or identifying patterns and relationships between numbers.

By practicing skip counting, recognizing multiplication patterns, utilizing visual representations, relating to real-life scenarios, and engaging in problem-solving activities, individuals can strengthen their unitizing skills. This not only enhances their numerical fluency but also supports their ability to work with numbers more efficiently and effectively.


Problem-solving plays a crucial role in applying number sense skills to real-world scenarios. It involves using mathematical concepts, logical reasoning, and critical thinking to analyze and solve complex problems. By integrating problem-solving with number sense, individuals can develop a deeper understanding of mathematics and enhance their overall mathematical proficiency.

Engaging in problem-solving tasks allows individuals to apply their number sense skills in practical and meaningful ways. It requires them to use their knowledge of subitizing, magnitude, counting, one-to-one correspondence, cardinality, hierarchical inclusion, part-part-whole relationships, compensation, and unitizing to tackle real-life situations that involve numbers and quantities. Problem-solving situations may range from calculating distances and measurements, managing budgets, analyzing data, or solving mathematical puzzles.

Problem-solving activities are instrumental in developing critical thinking and logical reasoning abilities. They require individuals to analyze problems, identify relevant information, make connections between different concepts, and devise effective problem-solving strategies. Through problem-solving, individuals learn to think creatively, make conjectures, test hypotheses, and justify their solutions. This process fosters a deeper understanding of mathematical concepts and promotes the development of critical thinking skills that are applicable beyond mathematics.

When approaching a problem, individuals typically follow a problem-solving cycle that includes understanding the problem, devising a plan, carrying out the plan, and reflecting on the solution. Understanding the problem involves interpreting and clarifying the given information, identifying the key components, and determining the desired outcome.

Devising a plan requires individuals to strategize and choose appropriate problem-solving techniques based on their number sense skills. Carrying out the plan involves implementing the chosen strategy, performing calculations, and analyzing the results. Finally, reflecting on the solution allows individuals to evaluate their approach, assess the reasonableness of the answer, and identify potential alternative strategies or improvements for future problem-solving situations.

By engaging in problem-solving activities that integrate number sense skills, individuals not only enhance their mathematical proficiency but also develop essential life skills such as critical thinking, logical reasoning, and problem-solving abilities. The ability to apply number sense effectively in problem-solving situations is a valuable asset that empowers individuals to navigate real-world challenges and make informed decisions based on their numerical understanding.

Problem-solving strategies that leverage number sense skills include:

1. Visualization and Mental Imagery: Use visualization techniques to mentally represent and manipulate numbers and quantities. For example, when solving a problem involving spatial relationships or measurements, visualize the objects or dimensions involved to gain a better understanding of the problem.

2. Breaking Down Complex Problems: Break down complex problems into smaller, more manageable parts. By identifying the key components and breaking them down into simpler subproblems, individuals can tackle each part separately, applying appropriate number sense skills to solve them before integrating the solutions to the larger problem.

3. Estimation and Approximation: Employ estimation and approximation techniques to simplify calculations. When faced with large numbers or complex calculations, round numbers to their nearest tens, hundreds, or other convenient values to make mental calculations more manageable. This strategy allows individuals to arrive at reasonable and approximate solutions quickly.

4. Logical Reasoning and Making Connections: Apply logical reasoning to analyze the problem, make connections between different concepts, and identify relevant strategies. Look for patterns, relationships, or similarities between the given problem and previously encountered problems to draw upon prior knowledge and experiences.

5. Utilizing Patterns and Relationships: Explore patterns and relationships within numbers to solve problems. Look for recurring patterns, sequences, or mathematical relationships that can provide insights or shortcuts to finding solutions. By leveraging these patterns and relationships, individuals can simplify calculations or make predictions.

By incorporating these problem-solving strategies into mathematical tasks, individuals can leverage their number sense skills effectively. These strategies encourage critical thinking, logical reasoning, and creative problem-solving, enabling individuals to approach mathematical challenges with confidence and develop a deeper understanding of numbers and their applications.

Integrating Number Sense Daily

By incorporating number sense into our daily teaching routines, we can provide a solid mathematical foundation and foster a deeper understanding of numbers. Here are two effective strategies that you, as teachers, can implement to seamlessly integrate number sense practices into your daily routine:

1. Energizing Warm-Up Activities: Start each math lesson with engaging warm-up activities that specifically target number sense. These activities can be quick, interactive, and designed to activate students’ mathematical thinking. For example, you can pose a mental math challenge, encourage students to estimate quantities or engage them in number talks where they share strategies for solving number-based problems. By incorporating these energizing warm-up activities, you set the stage for a productive math lesson while reinforcing essential number sense skills.

2. Engaging Math Centers and Games: Create math centers or interactive games that provide opportunities for students to practice and apply number sense concepts independently. These hands-on activities can be tailored to meet the diverse needs and abilities of your students. For instance, you can set up a counting center with manipulatives for one-to-one correspondence practice or introduce a number comparison game where students match numerals with their corresponding quantities. By incorporating these engaging math centers or games, you foster a supportive and interactive learning environment where students can explore number sense at their own pace. This math set of task cards are perfect additions to centers and your daily routine.

By integrating number sense into your daily routine through energizing warm-up activities and purposeful math centers or games, you can nurture a strong mathematical foundation in your students. These strategies not only reinforce key number sense skills but also promote critical thinking, collaboration, and a deeper understanding of numbers. Let’s embark on this journey together and witness the growth and confidence of our students as they develop their number sense abilities.


Interested in the mentioned resources? Grab them here:

Counting Collection
Math Intervention

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