We need students to be able to think mathematically. To be confident and capable problem solvers.

Unleashing the Power of Math for Real-World Challenges

It is time that we increase the value of our instruction, so that we can see the gains in student learning that we seek.


Delve into David’s math education expertise. Purchase his four impactful books directly from the seasoned author. Explore insights on retrieval practice, problem-solving, math literacy, differentiation, curriculum mapping, and year plans. Uncover a wealth of knowledge with ease.

Event Schedule

Stay in the loop with Dr. David Costello’s engaging in-person and virtual events. Discover valuable insights on mathematics education, facilitated by an experienced professional. Check out his event calendar to ensure you never miss an opportunity to enhance your knowledge and stay connected in the world of education.

Problem Toolbox

Use our Problem Toolbox to find the right problem for any key concept. You can tailor the problem type to meet the various learning needs in your classroom. Whether it is for teacher modelling or independent practice, you will have access to ready-to-use problems that support student learning.

Costello Math: Blog

The Costello Math blog is the go-to resource for teachers, school administrators, system leaders and everyone interested in staying up-to-date in mathematics. We explore hot topics in mathematics including the challenges teachers experience in classrooms, how we can engage students in meaning making and the debates surrounding current instructional approaches.

Video Library

Discover Costello Math

Embark on a math journey with Costello Math’s captivating video section! Join David as he unravels diverse tips and engaging presentations to demystify the world of numbers. Our videos are not just informative – they’re a dynamic showcase of effective and easily understood methods. Dive into a wealth of math wisdom that goes beyond the textbook, making learning both enjoyable and comprehensible. Get ready to elevate your math game with Costello Math’s video series – where understanding math is made simple and exciting!

Authored by Dr. David Costello

David has had the privilege of teaching multiple grade levels and working with a variety of teachers and schools. During this time, David has developed and identified effective instructional strategies that support students in making sense of mathematics.

From this experience, David has written four books that have been used by many teachers, schools and associations across Canada and the United States. Whether you are beginning your educational career, mid-way through it or nearing its conclusion, you will be able to immediately apply the strategies from David’s books into your classroom.

Messing around with Math

Ready-to-use problems that engage students in a better understanding of key math concepts.

Mathematizing Student Thinking

Connecting problem solving to everyday life and building capable and confident math learners.

Making Math Stick

Classroom Strategies that Support the Long-Term Understanding of Math Concepts.

Using What Works

Strategies for Developing a Literacy-Rich Environment in Math.

Testimonial - HRCE Principals

“David’s profound depth of knowledge coupled with an easy-going, accessible and collaborative approach created a supportive, participatory and engaging environment for teacher learning. As a result of the professional learning led by David, our teachers transformed their approach to teaching mathematics. The implementation of cumulative review and the data gathered from this strategy enabled teachers to focus their instruction and to close learning gaps”.

Testimonial - Statewide Math Organization

“Dr. David Costello provides helpful and useful resources for mathematics teachers to use in their classrooms. He delivered meaningful webinars that emphasized mathematical discourse and literacy among face-to-face, blended, and online mediums. He values the teaching profession and helped us work with our mathematics teachers across the state”.

Testimonial - Lead Teacher

“Demonstrating a strong understanding of implementing numeracy in the classroom, David Costello effectively highlights the importance of focusing on the process behind the product. He offers practical, effective strategies to help educators dive deeper into mathematical thinking with their students”.

Testimonial - Primary School Administrator

“Before working with Dr Costello, my school was consistently doing poorly on our standardized math assessments. David facilitated PD on core concepts and highlighted how to strengthen student understanding of these through manageable instructional practices. From this, our school is now scoring above the provincial average and teachers are seeing substantial improvements in student math understanding. We would love to work with him again! “

Testimonial - Elementary Principal

“My staff are enthusiastic about David’s work. They have developed professional development goals and growth plans focused on his work. Many have already ordered his latest book and are already talking about next year’s goals. I love that David’s work is motivating, practical and teacher-friendly”.

Testimonial - Combined Grade Teacher

“Teaching a combined grade class is very challenging. I felt as though I was teaching two separate lessons each day. When I started working with David Costello, I started to see the connections among various concepts and how math is a continuum. Along with this, his instructional strategies helped me differentiate between grade-level content and the learning needs of my students. It has completely reinvigorated me and how I see math. I would recommend Dr. Costello’s work to any math teacher.”

Testimonial - Curriculum Lead

“Highly engaging and informative, Dr Costello offers great strategies for both educators and students to go beyond the surface of mathematical thinking. Educators left his webinar feeling inspired to dive deeper into problem-solving with their students”.

Testimonial - Zachary Slayton - Middle School Principal

“Dr. Costello provided our staff with training that was relevant to our school goals and ready to use right away. The training was fun, and my teachers began to put what they learned to work the very next day. We look forward to working with him again in the future”.

Testimonial - TDSB Principal

“Our staff collaborated with David on his book, Using What Works. With David’s support, we were able to interrogate the strategies we use in our mathematics classes, and how we can create the environment and learning opportunities that lead our students to better understand. David has helped us to impact our instruction, and thus student learning, by using literacy-rich intentionality and planning to support our learners with strategies that work. Through our professional learning with David, we have been able to dive deeply into the continuum of building mathematics strategies and bring our learning into our classrooms”.


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