There are many excellent videos posted on the The Teaching Channel. An excellent series of videos highlights Math Routines by Kristin Gray. If you are interested in viewing instructional strategies such as Notice and Wonder, Which One Doesn't Belong, Number Strings, and a variety of other videos, you can find them on the teaching channel.
Numbers and Operations and Fractions Visual Models
Core Introduction (All Grades)
Beyond Right Answers (All Grades)
Counting Collections -- (K-1)
Dot Talks (K-2)
Teaching Math To The Common Core -- (3-6)
My favorite No -- (3-6)
Assessing using exit tickets -- (all grades)
Using talk moves -- (all grades)
Reasoning about division -- (3-5)
Leprechaun Traps: Addition within 100 -- (1-2)
Beyond Fingers: Place Value and the numbers 11-19 -- (K-1)
A Passion for Fractions -- (5)
Multiplying Whole Numbers and Fractions -- (4-5)
Preparation for fraction Multiplication -- (4-5)
Counting Collections By Ten -- (1-2)
Hint Cards -- (K-6)
Introduction to ratios and proportional relationships -- (6)
Applying understanding of ratios to fractions -- (6)
Reflection on teaching and learning ratios -- (6)
Collaboration -- (K-6)