Richard Bisk provides professional development for teachers to deepen their understanding of the mathematics they teach. He emphasizes helping teachers understand the logical structure and reasoning behind mathematics concepts. For elementary teachers, he focuses on number and operations since this provides the foundation for higher mathematics. Developing strong number sense in teachers helps them move away from rote memorization and foster understanding in students. Bisk has 16 years experience consulting with schools using Singapore-style textbooks, but his approach is effective for all teachers regardless of curriculum.